|
|||||||||
|
|
|
|
|
|
|
|
|
|
|
Prepublished online as a Blood First Edition Paper on April 17, 2002; DOI 10.1182/blood-2001-11-0066.
NEOPLASIA
From the Department of Haematology, Royal Liverpool
University Hospital, United Kingdom.
Established adverse prognostic factors in chronic lymphocytic
leukemia (CLL) include CD38 expression, relative lack of
IgVH mutation, and defects of the
TP53 gene. However, disruption of the p53 pathway can occur
through mechanisms other than TP53 mutation, and we have
recently developed a simple screening test that detects p53 dysfunction
due to mutation of the genes encoding either p53 or ATM, a kinase that
regulates p53. The present study was conducted to examine the
predictive value of this test and to establish the relationship between
p53 dysfunction, CD38 expression, and IgVH
mutation. CLL cells from 71 patients were examined for
IgVH mutation, CD38 expression, and p53
dysfunction (detected as an impaired p53/p21 response to ionizing
radiation). Survival data obtained from 69 patients were analyzed
according to each of these parameters. Relative lack of
IgVH mutation (less than 5%; n = 45), CD38
positivity (antigen expressed on more than 20% of malignant cells;
n = 19), and p53 dysfunction (n = 19) were independently confirmed
as adverse prognostic factors. Intriguingly, all p53-dysfunctional patients and all but one of the CD38+ patients had greater
than 5% IgVH mutation. Moreover, patients with
p53 dysfunction and/or CD38 positivity (n = 31) accounted for the
short survival of the less mutated group. These findings indicate that
the poor outcome associated with having less than 5%
IgVH mutation may be due to the
overrepresentation of high-risk patients with p53 dysfunction and/or
CD38 positivity within this group, and that CD38 B-cell chronic lymphocytic leukemia (CLL) is the
most common leukemia in the Western world and is characterized by the
accumulation of clonal mature B lymphocytes in the blood, bone marrow,
and secondary lymphoid tissues.1,2 One of the most
intriguing features of the disease is its clinical heterogeneity. Thus,
whereas some CLL patients survive for decades without requiring any
treatment, others die of drug-resistant disease within a year or two of
presentation.1,2
Sequencing of the B-cell receptor heavy chain gene
(IgVH) of CLL lymphocytes has revealed extensive
mutation in some cases.3 Because
IgVH mutation underlies the process of affinity
maturation and occurs in the germinal center of secondary lymphoid
follicles, such hypermutated cases have been considered to be clonal
expansions of postgerminal center (memory) B cells.3 In
contrast, the malignant lymphocytes from other patients have
IgVH genes that are less mutated; these cases
have been considered to represent clonal expansions of pregerminal
center (naive) B cells.3
Considerable interest was generated by the recent demonstration by 2 independent groups that the extent of IgVH
mutation can predict the clinical outcome in CLL.4,5 Thus,
patients with relatively unmutated IgVH genes
have a significantly shorter survival than patients with more extensive
IgVH mutation.
CD38 is a transmembrane glycoprotein that is widely expressed on a
range of hemic and nonhemic cell types.6 In normal
mature B cells, its expression is confined to the germinal center of secondary lymphoid follicles.7 There has been a
considerable amount of interest (and controversy) in the notion that
CD38 expression in CLL is associated with short survival and relative
lack of IgVH mutation.4,5,7-11
p53 is a transcription factor that is activated by DNA breaks and which
can induce apoptosis or cell-cycle arrest.12,13 By
orchestrating the repair or elimination of cells with damaged DNA, p53
maintains the integrity of the genome and thereby prevents clonal
progression.14 The protein also contributes to the
cytotoxicity of many anticancer agents,15 including purine
analogues commonly used in the treatment of CLL.16-18
Unsurprisingly, TP53 mutations are associated with an
adverse clinical outcome in a range of cancers, including
CLL.19-21
Identification of p53 defects in the routine clinical setting has been
improved recently by the development in this laboratory of a simple
functional test that examines the p53 response of malignant cells to
ionizing radiation.22 The test has demonstrated 2 types of
p53 dysfunction in CLL, which together affect up to one quarter of
cases overall. One defect is associated with the TP53
mutation and the other with inactivation of the gene encoding ATM, a kinase that regulates p53. Intriguingly, low ATM protein levels The aims of the present study were to establish the predictive value of
the p53 function test and to examine the relationship between p53
dysfunction, CD38 positivity, and relative lack of IgVH mutation.
CLL patients
IgVH mutation analysis
Detection of CD38 expression This was performed by fluorescence-activated cell sorting analysis of mononuclear cell preparations that had been double stained with phycoerythrin-conjugated anti-CD38 and fluorescein isothiocyanate-conjugated anti-CD19 (both from Becton Dickinson, San Jose, CA), as previously described.10Detection of functional defects of the p53 pathway CLL lymphocytes were exposed to ionizing radiation (5 Gy) and cultured in RPMI supplemented with 10 mg/mL bovine serum albumin. After 10 to 18 hours, the cells were lysed in radioimmunoprecipitation assay (RIPA) buffer and the lysates were examined for p53, p21, and BCL-2 proteins by Western blotting, as previously described.22 Type A p53 dysfunction (due to TP53 mutation) is characterized by increased baseline levels of p53 and impaired radiation-induced p21 up-regulation. Type B p53 dysfunction (due to ATM mutation) is characterized by impaired up-regulation of both p53 and p21. BCL-2 was used as a protein control because it is highly expressed in CLL cells,28 is unaffected by radiation,22 and is extracted in RIPA buffer from live cells only (unpublished observations, 2001), thereby controlling for the possibility that p53/p21 up-regulation was impaired because the cells were dead.Analysis of patient outcome Clinical information was retrieved retrospectively from case notes. Patient survival was analyzed using Kaplan-Meier survival curves and the log-rank test. Disease-specific survival was obtained by censoring those deaths that could not be explained by CLL or its treatment. Differences between patient groups in the time interval from diagnosis to blood collection were analyzed using the Mann-Whitney U test. The 2 test or Fisher
exact test was used to compare features between different patient
groups. Statistical significance was accepted at
P < .05.
Profile of p53 dysfunction, CD38 expression, and IgVH mutation CLL cells from 71 patients were examined for p53 dysfunction, CD38 expression, and IgVH mutation. Nineteen patients (26%) were found to have p53 dysfunction, detected as an impaired p53/p21 response to ionizing radiation. Eight (11%) had the type A defect associated with TP53 mutation, whereas 11 (15%) had the type B defect associated with ATM mutation (Figure 1). The proportion of B cells expressing CD38 varied from 0 to 82%, and the extent of IgVH mutation varied from 0 to 12.4%.
To confirm that p53 dysfunction, IgVH mutation, and CD38 expression had prognostic value within the present study, we separated patients according to each of these 3 criteria and constructed Kaplan-Meier curves. Survival data were available for 69 of the 71 patients. Adverse prognostic impact of p53 dysfunction Separating patients according to their p53 functional status (Figure 2) revealed that those with demonstrable dysfunction of the p53 pathway had a much shorter disease-specific survival than those with functionally normal p53 (median, 54 months versus not reached). Subdividing the p53 dysfunctional cases (not shown) revealed that patients with the type A p53 defect, associated with TP53 mutation, had a significantly shorter survival than patients with the type B defect, associated with ATM mutation (median, 38 versus 90 months; P = .0003). These findings indicate that the p53 function test is a powerful predictor of outcome in CLL.
Adverse prognostic impact of relative lack of IgVH mutation Normal CD5+ B cells have less than 5% IgVH mutation, whereas CLL cells may have less than or greater than 5%.3 However, most previous studies of IgVH mutation in CLL have employed a cutoff of 2% to define "mutated" and "unmutated" subgroups. In the present study, therefore, patients were divided into 3 groups: those with less than 2%, those with 2% to 5%, and those with greater than 5% IgVH mutation (Figure 3). As expected,4,5 patients with less than 2% mutation had a shorter disease-specific survival than those with greater than 5% mutation (median, 90 months versus not reached; P < .0001). The survival of patients with 2% to 5% mutation (median, 90 months) was similar to that of patients with less than 2% mutation (P = .43) and significantly shorter than that of patients with greater than 5% mutation (P = .0015). These data confirm the adverse prognostic importance of having relatively unmutated IgVH genes and indicate that in the present study, a cutoff value of 5% was better than 2% for defining CLL subgroups on the basis of this criterion.
Adverse prognostic impact of CD38 positivity Most previous reports of CD38 expression in CLL have defined CD38+ cases as those in which the antigen is expressed on at least 30% of the malignant cells, although in one recent large report,11 a lower threshold value of 20% was used. However, these considerations were not relevant to the present study because no patient had between 20% and 30% CD38 positivity. Arbitrarily taking the lower cutoff value (Figure 4), we found that CD38+ patients had a significantly shorter disease-specific survival than the CD38 group (median, 90 months versus not reached).
These data therefore extend our previous observations10 and
confirm the adverse prognostic importance of CD38 positivity in
the present study.
Having confirmed that p53 dysfunction, relative lack of
IgVH mutation, and CD38 positivity each had an
adverse impact on patient survival in the present study, we next
examined the relationships between these prognostic factors (Figure
5).
Association between CD38 expression and relative lack of IgVH mutation In keeping with previous findings from this and other laboratories,4,10 there was a skewed relationship between CD38 positivity and IgVH mutation (Figure 5). Thus, 18 of the 19 CD38+ patients (95%) had less than 5% IgVH mutation. Moreover, the single CD38+ patient exceeding this threshold value did so by only a narrow margin, having 5.12% mutation. In summary, CD38+ cases constituted 40% (18 of 45) of the group with less than 5% IgVH mutation and only 4% (1 of 26) of the group with greater than 5% mutation.Association between p53 dysfunction and relative lack of IgVH mutation Intriguingly, there was also a skewed relationship between p53 dysfunction and IgVH mutation (Figure 5). Thus, every p53-dysfunctional patient had less than 5% IgVH mutation. These cases therefore constituted 42% (19 of 45) of the group with less than 5% mutation and none of the group with greater than 5% mutation. There was no difference in the extent of IgVH mutation between cases with the type A versus the type B defect.Lack of association between CD38 positivity and p53 dysfunction There was no apparent association between p53 dysfunction and CD38 expression (Figure 5). Thus, 7 of the 19 p53-dysfunctional patients (37%) were CD38+, compared with 12 of the 52 patients with functionally normal p53 (23%). Conversely, among the 19 CD38+ patients, p53 dysfunction was present in 37% (7 of 19), as compared with 23% (12 of 52) of the CD38 cases.
Together, patients with p53 dysfunction and/or CD38 positivity (n = 31) accounted for 67% (30 of 45) of the group with less than 5% IgVH mutation but only 4% (1 of 26) of the group with greater than 5% IgVH mutation. In light of these observations, it was of interest to examine the extent to which patients with p53 dysfunction and/or CD38 positivity accounted for the short survival of the group with less mutated IgVH genes. Contribution of p53 dysfunction and CD38 positivity to the short survival of patients with less than 5% IgVH mutation Patients with CD38 positivity and/or p53 dysfunction had a considerably worse outcome than patients with neither of these features (median survival, 71 months versus not reached; P < .0001). Importantly, separating the CD38, p53-intact patients according to
IgVH status showed that those with less than 5%
IgVH mutation survived as well as those with greater than 5% mutation, with only one disease-related death occurring within the former group (Figure
6A). A similar relationship between the
survival curves was obtained when disease-unrelated deaths were
included in the analysis (Figure 6B). These data suggest that the poor
outcome associated with having less than 5%
IgVH mutation is due to the overrepresentation
of patients with p53 dysfunction and/or CD38 positivity within this
group, and that CD38 patients with functionally intact
p53 have a prolonged disease-specific survival that does not depend on
the extent of IgVH mutation.
The aims of the present study of CLL were to validate our screening test for p53 dysfunction and to examine the relationship between p53 dysfunction, IgVH mutation, and CD38 expression. An abnormal p53 function test was found to be strongly predictive of short survival, with the type A defect (due to TP53 mutation) being associated with a particularly poor outcome. When cases of CLL were separated according to their IgVH status, patients with 2% to 5% IgVH mutation were found to have a survival similar to that of patients with less than 2% mutation and considerably shorter than that of patients with greater than 5% mutation. Regarding CD38, patients expressing the antigen on more than 20% of their malignant cells had a survival disadvantage as compared with patients with a lower level of expression. Having confirmed within our patient group the predictive value of p53 dysfunction, IgVH mutation, and CD38 expression, we next examined the relationship between these prognostic factors. As expected, nearly all of the CD38+ patients had relatively unmutated IgVH genes. Intriguingly, the same was found to be true of patients with p53 dysfunction. Although some patients were simultaneously CD38+ and p53 dysfunctional, these 2 prognostic factors were not associated with one another. Because high-risk patients with p53 dysfunction and/or CD38 positivity represented about two thirds of the group with less than 5% IgVH mutation, it seemed possible that they might account for its short survival, and this was indeed found to be so. That CLL patients with p53 dysfunction have a short survival is entirely in keeping with the established importance of the p53 pathway in maintaining genomic integrity14 and mediating the action of certain cytotoxic agents, including purine analogues.15-18 It is also consistent with the adverse prognostic significance in CLL of deletions of 17p13 and 11q22-23, which involve the TP53 and ATM loci, respectively.29 Indeed, impairment of the p53 pathway may represent a single functional end point through which these (and possibly other) seemingly unrelated prognostic factors exert their deleterious effects. In contrast, it is unclear why CD38 positivity is associated with a short patient survival. It is possible that expression of CD38 confers to CLL cells a more malignant cellular phenotype. This seems plausible given that the antigen has an important role as a modulator of intracellular signaling30,31 and that cross-linking of CD38 up-regulates BCL-2 and inhibits apoptosis in normal mature B cells.32,33 Our observation that CLL patients with greater than 5%
IgVH mutation were nearly all CD38 Regarding the association between relatively unmutated IgVH genes and p53 dysfunction, there are, we suggest, a number of possible explanations. First, dysfunction of the p53 pathway might impair the capacity of the CLL precursor cell to undergo somatic hypermutation. Second, CLL lymphocytes with relatively unmutated IgVH genes might be selectively prone to the acquisition of genetic changes that result in p53 dysfunction. Third, p53 dysfunction might selectively facilitate the clonal expansion of CLL precursor cells with relatively unmutated IgVH genes. Fourth, the phenotype of tumor cells with extensively mutated IgVH genes might be altered in the presence of p53 dysfunction, such that the disease is not recognizable as CLL. At present, it is unclear which, if any, of these possibilities is correct. Our survival data led us to employ a cutoff of 5% for defining CLL
subgroups on the basis of IgVH mutation. This
choice of threshold value was further supported by the observed
relationships between IgVH mutation, CD38
expression, and p53 dysfunction. In contrast to our empirical approach,
most previous studies have aimed to separate patients on the basis of
whether the IgVH gene is in true germline
configuration. This theoretical approach is attractive because it has
implications for the identity of the normal counterpart cell and
whether antigen encounter has occurred. To separate "mutated" from
"unmutated" cases, a cutoff of 2% (rather than zero)
IgVH mutation has historically been used to avoid
mistaking unknown polymorphisms for true somatic mutations acquired
during the affinity maturation response to antigen.35 This
approach is clearly a compromise because many cases of CLL with up to
2% divergence from the accepted germline sequence are likely to have proper IgVH mutations. There are also problems
in using IgVH mutation to define whether antigen
encounter has occurred. For example, T-independent antigen stimulation
can produce memory B cells with unmutated IgVH
genes.36 Furthermore, only those
IgVH mutations resulting in amino acid changes
within the antigen binding site are functionally important in terms of
the affinity maturation response37; mutations of the
intervening framework regions are of unclear significance and cannot be
taken to indicate that affinity maturation These considerations clearly raise important questions concerning the biologic meaning of IgVH mutation in CLL and how IgVH subgroups should be defined. Indeed, it could be argued that CLL might be better regarded as a single entity with a continuously variable phenotype. This model predicts that, prior to clonal expansion, the precursor cell undergoes a varying amount of IgVH mutation, the extent of which is governed by the presence and nature of the stimulus (T-dependent versus T-independent antigen and/or intrinsic oncogenic signaling mimicking antigen) and the integrity of the cellular machinery required for hypermutation to occur. We speculate that these determining factors, and not the extent of somatic mutation per se, define the clinical behavior of the disease. It is important to note that the clinical samples upon which the present observations are based were not all obtained at disease presentation. Because it is unknown to what extent p53 dysfunction and CD38 expression may be acquired with time, caution should be exercised when applying our data to newly diagnosed patients. However, the diagnosis of CLL as a clinical event is of dubious relevance to the natural history of the disease. For example, it is universally accepted that in many patients, the disease is likely to have been present for many years prior to its initial detection and that diagnosis is frequently made by accident. Nevertheless, in the present study, the interval between diagnosis and blood collection was not significantly different between any of the subgroups analyzed. Furthermore, the observed frequencies of CD38 positivity (27%) and p53 dysfunction of each type (11% and 15% for the type A and B defects, respectively) were no greater than expected from any previous reports. Therefore, although we cannot formally exclude the possibility that p53 dysfunction or CD38 expression may have been acquired after diagnosis in the occasional patient, the above considerations suggest that such an occurrence is rare and unlikely to have had a significant impact on the findings. In summary, the present study provides a plausible explanation for the
poor clinical outcome of CLL patients with relatively unmutated
IgVH genes and demonstrates the marked
heterogeneity of such patients. From a clinical point of view, it will
be important to conduct prospective studies to establish the value of
p53 dysfunction and CD38 positivity in predicting the survival of newly
diagnosed patients and the response to different therapies. It will
also be important to gauge the extent to which these 2 features may be
acquired over time, particularly in patients with less than 5%
IgVH mutation. Nevertheless, the existing data
have unambiguous implications for patients with established p53
dysfunction and/or CD38 positivity. Indeed, the very poor outlook of
patients with p53 dysfunction
Submitted November 28, 2001; accepted January 28, 2002.
Prepublished online as Blood First Edition Paper, April 17, 2002; DOI 10.1182/blood-2001-11-0066.
Supported by grants from The Leukaemia Research Fund (United Kingdom) and the Royal Liverpool & Broadgreen University Hospitals Trust R&D Fund.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Andrew R. Pettitt, Department of Haematology, Royal Liverpool University Hospital, Liverpool, L7 8XP United Kingdom; e-mail: andrew.pettitt{at}rlbuh-tr.nwest.nhs.uk.
1.
Rozman C, Montserrat E.
Chronic lymphocytic leukemia.
N Engl J Med.
1995;333:1052-1057
2.
Caligaris-Capio F, Hamblin TJ.
B-cell chronic lymphocytic leukemia: a bird of a different feather.
J Clin Oncol.
1999;17:399-408 3. Fais F, Ghiotto F, Hashimoto S, et al. Chronic lymphocytic leukemia B cells express restricted sets of mutated and unmutated antigen receptors. J Clin Invest. 1998;102:1515-1525[Medline] [Order article via Infotrieve].
4.
Damle RN, Wasil T, Fais F, et al.
Ig V gene mutation status and CD38 expression as novel prognostic indicators in chronic lymphocytic leukemia.
Blood.
1999;94:1840-1847
5.
Hamblin TJ, Davis Z, Gardiner A, Oscier DG, Stevenson FK.
Unmutated IgV(H) genes are associated with a more aggressive form of chronic lymphocytic leukemia.
Blood.
1999;94:1848-1854 6. Malavasi J, Funaro A, Roggero S, et al. Human CD38: a glycoprotein in search of a function. Immunol Today. 1994;15:95-97[CrossRef][Medline] [Order article via Infotrieve].
7.
Naylor M, Capra JD.
Mutational status of Ig VH genes provides clinically valuable information in B-cell chronic lymphocytic leukemia.
Blood.
1999;94:1837-1839 8. Del Poeta G, Maurillo L, Venditti A, et al. CD38 expression identifies two distinct subsets in B-chronic lymphocytic leukemia (B-CLL). Blood. 2000;96(suppl 1):366a.
9.
Thunberg U, Johnson A, Roos G, et al.
CD38 expression is a poor predictor for VH gene mutational status and prognosis in chronic lymphocytic leukemia.
Blood.
2001;97:1892-1893
10.
Matrai Z, Lin K, Dennis M, et al.
CD38 expression and IgVH gene mutation in B-cell chronic lymphocytic leukemia.
Blood.
2001;97:1902-1903
11.
Ibrahim S, Keating M, Do K-A, et al.
CD38 expression as an important prognostic factor in B-cell chronic lymphocytic leukemia.
Blood.
2001;98:181-186
12.
Ko LJ, Prives C.
p53: puzzle and paradigm.
Genes Dev.
1996;10:1054-1072 13. Levine AJ. p53, the cellular gatekeeper for growth and division. Cell. 1997;88:323-331[CrossRef][Medline] [Order article via Infotrieve]. 14. Lane DP. p53, guardian of the genome. Nature. 1992;358:15-16[CrossRef][Medline] [Order article via Infotrieve]. 15. Lowe SW, Ruley HE, Jacks T, Housman DE. p53-dependent apoptosis modulates the cytotoxicity of anticancer agents. Cell. 1993;74:957-967[CrossRef][Medline] [Order article via Infotrieve]. 16. Pettitt AR, Clarke AR, Cawley JC, Griffiths SD. Purine analogues kill resting lymphocytes by p53-dependent and -independent mechanisms. Br J Haematol. 1999;105:986-988[CrossRef][Medline] [Order article via Infotrieve]. 17. Pettitt AR, Sherrington PD, Cawley JC. The effect of p53 dysfunction on purine analogue cytotoxicity in chronic lymphocytic leukaemia. Br J Haematol. 1999;106:1049-1051[CrossRef][Medline] [Order article via Infotrieve].
18.
Pettitt AR, Sherrington PD, Cawley JC.
Role of poly(ADP-ribosyl)ation in the killing of chronic lymphocytic leukemia cells by purine analogues.
Cancer Res.
2000;60:4187-4193
19.
El Rouby S, Thomas A, Costin D, et al.
p53 gene mutation in B-cell chronic lymphocytic leukemia is associated with drug resistance and is independent of MDR1/MDR3 gene expression.
Blood.
1993;82:3452-3459
20.
Wattel E, Preudhomme C, Hecquet B, et al.
p53 mutations are associated with resistance to chemotherapy and short survival in hematologic malignancies.
Blood.
1994;84:3148-3157
21.
Dohner H, Fischer K, Bentz M, et al.
p53 gene deletion predicts for poor survival and non-response to therapy with purine analogs in chronic B-cell leukemias.
Blood.
1995;85:1580-1589
22.
Pettitt AR, Sherrington PD, Stewart G, Cawley JC, Taylor AMR, Stankovic T.
p53 dysfunction in B-cell chronic lymphocytic leukemia: inactivation of ATM as an alternative to TP53 mutation.
Blood.
2001;98:814-822 23. Stankovic T, Weber P, Stewart G, et al. Inactivation of ataxia telangiectasia mutated gene in chronic lymphocytic leukaemia. Lancet. 1999;353:26-29[CrossRef][Medline] [Order article via Infotrieve].
24.
Starostik P, Manshouri T, O'Brien S, et al.
Deficiency of ATM protein expression defines an aggressive subgroup of B-cell chronic lymphocytic leukemia.
Cancer Res.
1998;58:4552-4557 25. Campbell MJ, Zelenetz AD, Levy S, Levy R. Use of family specific leader region primers for PCR amplification of the human heavy chain variable region gene repertoire. Mol Immunol. 1992;29:193-203[CrossRef][Medline] [Order article via Infotrieve].
26.
Don RH, Cox PT, Wainwright BJ, Baker K, Mattick JS.
`Touchdown' PCR to circumvent spurious priming during gene amplification.
Nucleic Acids Res.
1991;19:4008 27. Tomlinson IM, Williams SC, Corbett SJ, Cox JBL, Winter G. V-BASE Sequence Directory. Cambridge United Kingdom: MRC Centre for Protein Engineering; 1996.
28.
Hanada M, Delia D, Aiello A, Stadtmauer E, Reed JC.
bcl-2 gene hypomethylation and high-level expression in B-cell chronic lymphocytic leukemia.
Blood.
1993;82:1820-1828
29.
Dohner H, Stilgenbauer S, Benner A, et al.
Genomic aberrations and survival in chronic lymphocytic leukemia.
N Engl J Med.
2000;343:1910-1916
30.
Howard S, Grimaldi JC, Bazan JF, et al.
Formation and hydrolysis of cyclic ADP-ribose catalyzed by lymphocyte antigen CD38.
Science.
1993;262:1056-1059 31. Summerhill RJ, Jackson DG, Galione A. Human CD38 catalyses the production of cyclic ADPribose. FEBS Lett. 1993;335:231-233[CrossRef][Medline] [Order article via Infotrieve]. 32. Zupo S, Rugari E, Dono M, Tamborelli G, Malavasi F, Ferrarini M. CD38 signaling by agonistic monoclonal antibody prevents apoptosis of human germinal center B cells. Eur J Immunol. 1994;24:1218-1222[Medline] [Order article via Infotrieve]. 33. Santos-Argumedo L, Teixira C, Preece G, et al. B-lymphocyte surface molecule mediating activation and protection from apoptosis via calcium channels. J Immunol. 1993;151:3119-3130[Abstract]. 34. Bauvois B, Durant L, Laboureau J, et al. Upregulation of CD38 expression in leukemic B cells by interferon types I and II. J Interferon Cytokine Res. 1999;19:1059-1066[CrossRef][Medline] [Order article via Infotrieve]. 35. Matsuda F, Shin EK, Nagaoka H, et al. Structure and physical map of 64 variable segments in the 3'0.8-megabase region of the human immunoglobulin heavy-chain locus. Nat Genet. 1993;3:88-94[CrossRef][Medline] [Order article via Infotrieve].
36.
Liu Y-J.
Sites of B lymphocyte selection, activation and tolerance in spleen.
J Exp Med.
1997;186:625-629
37.
Schettino EW, Ceratti A, Chiorazzi N, Casali P.
Lack of intraclonal diversification in Ig heavy and light chain genes expressed by CD5+ IgM+ chronic lymphocytic leukemia B cells: a multiple time point analysis.
J Immunol.
1998;160:820-830
© 2002 by The American Society of Hematology.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|
 |
|
  T. Zenz, S. Habe, T. Denzel, J. Mohr, D. Winkler, A. Buhler, A. Sarno, S. Groner, D. Mertens, R. Busch, et al. Detailed analysis of p53 pathway defects in fludarabine-refractory chronic lymphocytic leukemia (CLL): dissecting the contribution of 17p deletion, TP53 mutation, p53-p21 dysfunction, and miR34a in a prospective clinical trial Blood, September 24, 2009; 114(13): 2589 - 2597. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. G. Johnson, P. D. Sherrington, A. Carter, K. Lin, T. Liloglou, J. K. Field, and A. R. Pettitt A Novel Type of p53 Pathway Dysfunction in Chronic Lymphocytic Leukemia Resulting from Two Interacting Single Nucleotide Polymorphisms within the p21 Gene Cancer Res., June 15, 2009; 69(12): 5210 - 5217. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. A. Hernandez, A. E. Rodriguez, M. Gonzalez, R. Benito, C. Fontanillo, V. Sandoval, M. Romero, G. Martin-Nunez, A. G. de Coca, R. Fisac, et al. A high number of losses in 13q14 chromosome band is associated with a worse outcome and biological differences in patients with B-cell chronic lymphoid leukemia Haematologica, March 1, 2009; 94(3): 364 - 371. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. BOELENS, S. LUST, B. VANHOECKE, and F. OFFNER Chronic Lymphocytic Leukaemia Anticancer Res, February 1, 2009; 29(2): 605 - 615. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Zenz, A. Krober, K. Scherer, S. Habe, A. Buhler, A. Benner, T. Denzel, D. Winkler, J. Edelmann, C. Schwanen, et al. Monoallelic TP53 inactivation is associated with poor prognosis in chronic lymphocytic leukemia: results from a detailed genetic characterization with long-term follow-up Blood, October 15, 2008; 112(8): 3322 - 3329. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Veldurthy, M. Patz, S. Hagist, C. P. Pallasch, C.-M. Wendtner, M. Hallek, and G. Krause The kinase inhibitor dasatinib induces apoptosis in chronic lymphocytic leukemia cells in vitro with preference for a subgroup of patients with unmutated IgVH genes Blood, August 15, 2008; 112(4): 1443 - 1452. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Malavasi, S. Deaglio, A. Funaro, E. Ferrero, A. L. Horenstein, E. Ortolan, T. Vaisitti, and S. Aydin Evolution and Function of the ADP Ribosyl Cyclase/CD38 Gene Family in Physiology and Pathology Physiol Rev, July 1, 2008; 88(3): 841 - 886. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Hallek, B. D. Cheson, D. Catovsky, F. Caligaris-Cappio, G. Dighiero, H. Dohner, P. Hillmen, M. J. Keating, E. Montserrat, K. R. Rai, et al. Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the International Workshop on Chronic Lymphocytic Leukemia updating the National Cancer Institute-Working Group 1996 guidelines Blood, June 15, 2008; 111(12): 5446 - 5456. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. M. Ghia, S. Jain, G. F. Widhopf II, L. Z. Rassenti, M. J. Keating, W. G. Wierda, J. G. Gribben, J. R. Brown, K. R. Rai, J. C. Byrd, et al. Use of IGHV3-21 in chronic lymphocytic leukemia is associated with high-risk disease and reflects antigen-driven, post-germinal center leukemogenic selection Blood, May 15, 2008; 111(10): 5101 - 5108. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Gattei, P. Bulian, M. I. Del Principe, A. Zucchetto, L. Maurillo, F. Buccisano, R. Bomben, M. Dal-Bo, F. Luciano, F. M. Rossi, et al. Relevance of CD49d protein expression as overall survival and progressive disease prognosticator in chronic lymphocytic leukemia Blood, January 15, 2008; 111(2): 865 - 873. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Austen, A. Skowronska, C. Baker, J. E. Powell, A. Gardiner, D. Oscier, A. Majid, M. Dyer, R. Siebert, A. M. Taylor, et al. Mutation Status of the Residual ATM Allele Is an Important Determinant of the Cellular Response to Chemotherapy and Survival in Patients With Chronic Lymphocytic Leukemia Containing an 11q Deletion J. Clin. Oncol., December 1, 2007; 25(34): 5448 - 5457. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. R. Grever, D. M. Lucas, G. W. Dewald, D. S. Neuberg, J. C. Reed, S. Kitada, I. W. Flinn, M. S. Tallman, F. R. Appelbaum, R. A. Larson, et al. Comprehensive Assessment of Genetic and Molecular Features Predicting Outcome in Patients With Chronic Lymphocytic Leukemia: Results From the US Intergroup Phase III Trial E2997 J. Clin. Oncol., March 1, 2007; 25(7): 799 - 804. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Lin, M. A. Glenn, R. J. Harris, A. D. Duckworth, S. Dennett, J. C. Cawley, M. Zuzel, and J. R. Slupsky c-Abl Expression in Chronic Lymphocytic Leukemia Cells: Clinical and Therapeutic Implications. Cancer Res., August 1, 2006; 66(15): 7801 - 7809. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. W. L. Yee and S. M. O'Brien Chronic Lymphocytic Leukemia: Diagnosis and Treatment Mayo Clin. Proc., August 1, 2006; 81(8): 1105 - 1129. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Kojima, M. Konopleva, T. McQueen, S. O'Brien, W. Plunkett, and M. Andreeff Mdm2 inhibitor Nutlin-3a induces p53-mediated apoptosis by transcription-dependent and transcription-independent mechanisms and may overcome Atm-mediated resistance to fludarabine in chronic lymphocytic leukemia Blood, August 1, 2006; 108(3): 993 - 1000. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Montserrat, C. Moreno, J. Esteve, A. Urbano-Ispizua, E. Gine, and F. Bosch How I treat refractory CLL Blood, February 15, 2006; 107(4): 1276 - 1283. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Chiorazzi and M. Ferrarini Evolving View of the In-Vivo Kinetics of Chronic Lymphocytic Leukemia B Cells Hematology, January 1, 2006; 2006(1): 273 - 278. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. L. Abbott Chronic Lymphocytic Leukemia: Recent Advances in Diagnosis and Treatment Oncologist, January 1, 2006; 11(1): 21 - 30. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Marasca, R. Maffei, M. Morselli, P. Zucchini, I. Castelli, S. Martinelli, M. Fontana, S. Ravanetti, M. Curotti, G. Leonardi, et al. Immunoglobulin Mutational Status Detected through Single-Round Amplification of Partial VH Region Represents a Good Prognostic Marker for Clinical Outcome in Chronic Lymphocytic Leukemia J. Mol. Diagn., November 1, 2005; 7(5): 566 - 574. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Austen, J. E. Powell, A. Alvi, I. Edwards, L. Hooper, J. Starczynski, A. M. R. Taylor, C. Fegan, P. Moss, and T. Stankovic Mutations in the ATM gene lead to impaired overall and treatment-free survival that is independent of IGVH mutation status in patients with B-CLL Blood, November 1, 2005; 106(9): 3175 - 3182. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Allsup, A. S. Kamiguti, K. Lin, P. D. Sherrington, Z. Matrai, J. R. Slupsky, J. C. Cawley, and M. Zuzel B-Cell Receptor Translocation to Lipid Rafts and Associated Signaling Differ between Prognostically Important Subgroups of Chronic Lymphocytic Leukemia Cancer Res., August 15, 2005; 65(16): 7328 - 7337. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Raval, D. M. Lucas, J. J. Matkovic, K. L. Bennett, S. Liyanarachchi, D. C. Young, L. Rassenti, T. J. Kipps, M. R. Grever, J. C. Byrd, et al. TWIST2 Demonstrates Differential Methylation in Immunoglobulin Variable Heavy Chain Mutated and Unmutated Chronic Lymphocytic Leukemia J. Clin. Oncol., June 10, 2005; 23(17): 3877 - 3885. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Chiorazzi, K. R. Rai, and M. Ferrarini Chronic Lymphocytic Leukemia N. Engl. J. Med., February 24, 2005; 352(8): 804 - 815. [Full Text] [PDF]
|
|
|
|
|
|
P. Ghia, K. Stamatopoulos, C. Belessi, C. Moreno, S. Stella, G. Guida, A. Michel, M. Crespo, N. Laoutaris, E. Montserrat, et al. Geographic patterns and pathogenetic implications of IGHV gene usage in chronic lymphocytic leukemia: the lesson of the IGHV3-21 gene Blood, February 15, 2005; 105(4): 1678 - 1685. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. R. Pettitt, A. Carter, K. Lin, P. D. Sherrington, M. Atherton, K. Pearson, A. Douglas, A. Burford, V. Brito-Babapulle, E. Matutes, et al. Associations between Chromosomal Aberrations and Functional Impairment of the P53 Pathway in Chronic Lymphocytic Leukaemia. Blood (ASH Annual Meeting Abstracts), November 16, 2004; 104(11): 953 - 953. [Abstract]
|
|
|
|
|
|
G. F. Widhopf II, L. Z. Rassenti, T. L. Toy, J. G. Gribben, W. G. Wierda, and T. J. Kipps Chronic lymphocytic leukemia B cells of more than 1% of patients express virtually identical immunoglobulins Blood, October 15, 2004; 104(8): 2499 - 2504. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Haslinger, N. Schweifer, S. Stilgenbauer, H. Dohner, P. Lichter, N. Kraut, C. Stratowa, and R. Abseher Microarray Gene Expression Profiling of B-Cell Chronic Lymphocytic Leukemia Subgroups Defined by Genomic Aberrations and VH Mutation Status J. Clin. Oncol., October 1, 2004; 22(19): 3937 - 3949. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Z. Rassenti, L. Huynh, T. L. Toy, L. Chen, M. J. Keating, J. G. Gribben, D. S. Neuberg, I. W. Flinn, K. R. Rai, J. C. Byrd, et al. ZAP-70 Compared with Immunoglobulin Heavy-Chain Gene Mutation Status as a Predictor of Disease Progression in Chronic Lymphocytic Leukemia N. Engl. J. Med., August 26, 2004; 351(9): 893 - 901. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. Moshynska, K. Sankaran, P. Pahwa, and A. Saxena Prognostic Significance of a Short Sequence Insertion in the MCL-1 Promoter in Chronic Lymphocytic Leukemia J Natl Cancer Inst, May 5, 2004; 96(9): 673 - 682. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Lozanski, N. A. Heerema, I. W. Flinn, L. Smith, J. Harbison, J. Webb, M. Moran, M. Lucas, T. Lin, M. L. Hackbarth, et al. Alemtuzumab is an effective therapy for chronic lymphocytic leukemia with p53 mutations and deletions Blood, May 1, 2004; 103(9): 3278 - 3281. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. T. Jones, E. Addison, J. M. North, M. W. Lowdell, A. V. Hoffbrand, A. B. Mehta, K. Ganeshaguru, N. I. Folarin, and R. G. Wickremasinghe Geldanamycin and herbimycin A induce apoptotic killing of B chronic lymphocytic leukemia cells and augment the cells' sensitivity to cytotoxic drugs Blood, March 1, 2004; 103(5): 1855 - 1861. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. D. Shanafelt, S. M. Geyer, and N. E. Kay Prognosis at diagnosis: integrating molecular biologic insights into clinical practice for patients with CLL Blood, February 15, 2004; 103(4): 1202 - 1210. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Byrd, S. Stilgenbauer, and I. W. Flinn Chronic Lymphocytic Leukemia Hematology, January 1, 2004; 2004(1): 163 - 183. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Stankovic, M. Hubank, D. Cronin, G. S. Stewart, D. Fletcher, C. R. Bignell, A. J. Alvi, B. Austen, V. J. Weston, C. Fegan, et al. Microarray analysis reveals that TP53- and ATM-mutant B-CLLs share a defect in activating proapoptotic responses after DNA damage but are distinguished by major differences in activating prosurvival responses Blood, January 1, 2004; 103(1): 291 - 300. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. A. Davis, J. A. Orchard, M. M. Corcoran, and D. G. Oscier Divergence from the germ-line sequence in unmutated chronic lymphocytic leukemia is due to somatic mutation rather than polymorphisms Blood, October 15, 2003; 102(8): 3075 - 3075. [Full Text] [PDF]
|
|
|
|
|
|
D. Kienle, A. Krober, T. Katzenberger, G. Ott, E. Leupolt, T. F. E. Barth, P. Moller, A. Benner, A. Habermann, H. K. Muller-Hermelink, et al. VH mutation status and VDJ rearrangement structure in mantle cell lymphoma: correlation with genomic aberrations, clinical characteristics, and outcome Blood, October 15, 2003; 102(8): 3003 - 3009. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Lin, S. Manocha, R. J. Harris, Z. Matrai, P. D. Sherrington, and A. R. Pettitt High frequency of p53 dysfunction and low level of VH mutation in chronic lymphocytic leukemia patients using the VH3-21 gene segment Blood, August 1, 2003; 102(3): 1145 - 1146. [Full Text] [PDF]
|
|
|
|
|
|
A. Guarini, G. Gaidano, F. R. Mauro, D. Capello, F. Mancini, M. S. De Propris, M. Mancini, E. Orsini, M. Gentile, M. Breccia, et al. Chronic lymphocytic leukemia patients with highly stable and indolent disease show distinctive phenotypic and genotypic features Blood, August 1, 2003; 102(3): 1035 - 1041. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Wiestner, A. Rosenwald, T. S. Barry, G. Wright, R. E. Davis, S. E. Henrickson, H. Zhao, R. E. Ibbotson, J. A. Orchard, Z. Davis, et al. ZAP-70 expression identifies a chronic lymphocytic leukemia subtype with unmutated immunoglobulin genes, inferior clinical outcome, and distinct gene expression profile Blood, June 15, 2003; 101(12): 4944 - 4951. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Crespo, F. Bosch, N. Villamor, B. Bellosillo, D. Colomer, M. Rozman, S. Marce, A. Lopez-Guillermo, E. Campo, and E. Montserrat ZAP-70 Expression as a Surrogate for Immunoglobulin-Variable-Region Mutations in Chronic Lymphocytic Leukemia N. Engl. J. Med., May 1, 2003; 348(18): 1764 - 1775. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Sanchez-Beato, A. Sanchez-Aguilera, and M. A. Piris Cell cycle deregulation in B-cell lymphomas Blood, February 15, 2003; 101(4): 1220 - 1235. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Ghia, G. Guida, S. Stella, D. Gottardi, M. Geuna, G. Strola, C. Scielzo, and F. Caligaris-Cappio The pattern of CD38 expression defines a distinct subset of chronic lymphocytic leukemia (CLL) patients at risk of disease progression Blood, February 15, 2003; 101(4): 1262 - 1269. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Keating, N. Chiorazzi, B. Messmer, R. N. Damle, S. L. Allen, K. R. Rai, M. Ferrarini, and T. J. Kipps Biology and Treatment of Chronic Lymphocytic Leukemia Hematology, January 1, 2003; 2003(1): 153 - 175. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
 |
|||||||
 |
 |
 |
 |
 |
 |
 |
 |
||
| Copyright © 2002 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
Top
Abstract
Introduction
an imperfect surrogate for ATM
mutations
, 
, µ) antisense primers was
employed.
