|
|
 Previous Article | Table of Contents | Next Article 
Blood, Vol. 91 No. 3 (February 1), 1998:
pp. 1029-1036
Lung-Resistance-Related Protein Expression Is a Negative Predictive
Factor for Response to Conventional Low but not to Intensified Dose
Alkylating Chemotherapy in Multiple Myeloma
By
H.G.P. Raaijmakers,
M.A.I. Izquierdo,
H.M. Lokhorst,
C. de Leeuw,
J.A.M. Belien,
A.C. Bloem,
A.W. Dekker,
R.J. Scheper, and
P. Sonneveld
From the Departments of Haematology and Immunology, the University
Hospital Utrecht; the Department of Haematology, University Hospital
Rotterdam Dijkzigt, Rotterdam; and the Department of Pathology,
University Hospital Vrije Universiteit, Amsterdam, the Netherlands.
 |
ABSTRACT |
This study was undertaken to assess the significance of
lung-resistance related protein (LRP) expression in plasma cells from untreated multiple myeloma (MM) patients and to determine whether LRP
was associated with a poor response and survival in patients treated
with different dose regimens of melphalan. Seventy untreated patients
received conventional oral dose melphalan (0.25 mg/kg, day 1 to 4)
combined with prednisone (MP) or intravenous intermediate-IDM; 70 mg/m2) or high- (140 mg/m2) dose Melphalan
(HDM). LRP expression was assessed with immunocytochemistry using the
LRP-56 monoclonal antibody. LRP expression was found in 47% of
patients. In the MP treated patients, LRP expression was a significant
prognostic factor regarding response induction (P < .05),
event free survival (P < .003), and overall survival (P < .001). In the intensified dose melphalan treated
patients LRP did not have a prognostic value. The response rates of
LRP-positive patients to MP and IDM/HDM were 18% versus 81%,
respectively (P < .0001). We conclude that LRP is
frequently expressed in untreated MM patients and is an independent
predictor for response and survival in patients treated with MP.
Pretreatment assessment of LRP identifies a subpopulation of patients
with a poor probability of response to conventional dose melphalan.
Dose intensification of melphalan is likely to overcome LRP-mediated
resistance.
| |
INTRODUCTION |
ALKYLATING AGENTS and corticosteroids are
still the mainstay of therapy for patients with multiple myeloma
(MM).1,2 However, only approximately 50% to 60% of
patients respond to oral melphalan and prednisone in conventional dose
resulting in a median response duration of 1 to 2 years and a median
survival of about 3 to 4 years. Dose-intensification studies have shown
a dose-response relationship for melphalan3-5 in MM;
therefore, high-dose melphalan has been used to improve response rates
and survival.
Melphalan, like other alkylating agents, exerts its cytotoxic effect
through the covalent linkage of alkyl groups to DNA. Resistance against
alkylating agents includes both cellular and extracellular factors. In
cell line studies resistance to melphalan has been attributed to a
decreased drug uptake caused by alterations in either the number or the
affinity of membrane-bound proteins.6 An alternative
explanation may be an increased cellular detoxification by glutathione
S-transferases.7 So far, studies in hematological malignancies such as MM have failed to show a role of these laboratory findings in clinical specimens.8 Multiple drug resistance
(MDR) has been identified as an important path of drug resistance in MM. MDR is the phenomenon of cancer cells developing cross-resistance to a variety of structurally unrelated chemotherapeutic compounds such
as vinca-alkaloids, anthracyclines, and
epipodophyllotoxins.9 MDR is associated with the expression
of the drug transport mediating proteins P-glycoprotein (PgP) and the
multidrug resistance-related protein (MRP).10 The
increasing evidence of additional mechanisms of MDR led recently to the
identification of a novel protein associated with MDR, originally
termed the lung-resistance protein (LRP).
The LRP gene has recently been cloned and identified as the human p110
major vault protein.11 Vaults are novel cellular organelles
first described by Kedersha and Rome in 1986,12 which are
thought to mediate intracellular transport of a wide variety of
substrates. LRP has been found to be widely distributed in human normal
tissues and in tumors, closely reflecting the susceptibility to
chemotherapy of different tumor types.13 Importantly,
recent studies in myeloma and other human cancer cell lines relate LRP expression to resistance against the alkylating agent
melphalan14,15 (and W.S. Dalton et al, personal
communication, July 1997).
In the current study we have assessed LRP expression in myeloma
patients, and based on these results we introduce this MDR-related protein as a putative important marker of clinical resistance to the
alkylating agent melphalan resulting in an adverse prognosis. Moreover,
we describe the overcoming of LRP-related resistance against melphalan
by dose intensification.
| |
PATIENTS AND METHODS |
The study was performed on nonselected, sequentially stored frozen
cytocentrifuge slides prepared from Ficoll-Hypaque-purified bone
marrow aspirates obtained from all MM patients with newly diagnosed
disease who were treated with melphalan-based regimens between January
1987 and November 1995.
Additionally, bone marrow aspirates of three normal donors for
allogeneic bone marrow transplantation (BMT) and the aspirates of five
patients with monoclonal gammopathy of undetermined significance (MGUS)
were studies for LRP expression.
Patients.
Seventy unselected patients treated at the Departments of Haematology
of the University Hospital Utrecht or the University Hospital Rotterdam
Dijkzigt were studied. Clinical staging was defined according to the
criteria proposed by Salmon and Durie.16 Median age of
patients treated with conventional-dose oral melphalan and prednisone
was 67 years. Patients treated with intravenous (IV) intermediate- or
high-dose melphalan were median 52 years. The performance status was
determined according to the criteria of the Eastern Cooperative
Oncology Group (ECOG): 0, normal; 1, ambulant with symptoms; 2, bedrest
less than 50% of the day; 3, bedrest greater than 50% of the day; 4, bedrest all day. The patient characteristics are summarized in Table
1.
Chemotherapy regimens and response evaluation.
Patients received melphalan as first-line treatment, either in
combination with prednisone (MP, 38 patients) or as monotherapy in
intermediate dose (IDM, 20 patients) or high dose (HDM, 12 patients).
Patients under 65 years of age were candidates for IDM or HDM, unless
they refused intensive treatment. Patients refusing intensive treatment
and patients over 65 years received MP. Performance status was no
selection criterium for treatment modality. The intermittent MP regimen
consisted of oral melphalan 0.25 mg/kg/d and prednisone 2 mg/kg/d
administered for 4 days. Courses were repeated every 6 weeks.
IDM (melphalan 70 mg/m2) was administered by rapid IV
infusion. Two courses of IDM were given with an interval of 6 weeks.17 The HDM regimen (140 mg/m2) consisted
of a single dose. Response was determined by standard criteria for
myeloma response.18 A partial response was defined as a
reduction of at least 50% in serum M protein or urinary light chain
concentration with no progression of lytic bone lesions, without
increase of bone pain or anemia. A complete response (CR) was defined
as complete disappearance of myeloma proteins from serum and urine and
normalization of the bone marrow. Response in patients treated with MP
was determined after 4 courses, or earlier when progression was
obvious. When a partial response ( 50% reduction in M protein) was
achieved, therapy was continued for at least 1 year. Patients with a
minimal response (between 25% and 50% reduction in M protein)
received another four courses. Patients unresponsive after four courses
(less than 25% reduction in M-protein concentration) and patients with
a minimal response after four courses but no further improvement of
response after eight courses, continued with second-line chemotherapy,
usually a combination of vincristine, adriamycin, and dexamethasone
(VAD). Patients treated with IDM or HDM were evaluated 2 months after the second IDM or single-dose HDM, respectively. Nonresponding patients
were also treated with VAD.
Immunocytochemical staining of LRP.
LRP expression was determined by an alkaline phosphatase
immunocytochemical detection method19 using the specific
murine monoclonal antibody (MoAb) LRP-56 (IgG2b) that was obtained
after immunization of mice with the non-Pgp multidrug-resistant human nonsmall lung cancer cell line SW-1573/2R120.14 Bone marrow cells were separated by Ficoll-Hypaque, washed twice with minimal essential medium (MEM; GIBCO, Grand Island, NY) and stored at  20°C
until use. Cytocentrifuged slides were airdried overnight and fixed in
acetone for 10 minutes.
After preincubation for 20 minutes with 10% rabbit serum in
phosphate-buffered saline plus 1% bovine serum albumin (PBS/BSA; Sigma
Chemical Co, St Louis, MO), cytospins were incubated with LRP-56
(diluted 1:500 in 1% BSA) or with idiotype matched control (nonspecific mouse IgG-1; Cappel: Organon Teknica
50327/36345) for 1.5 hours. Next, rabbit anti-mouse immunoglobulin
(RAM; Dakopatts Z 259, DAKO Corp, Glastrup, Denmark) diluted 1:25 for 1 hour was added followed by incubation with alkaline phosphatase
substrate (APAAP; Dakopatts D 651, DAKO), diluted 1:50 for 1 hour.
Incubations with RAM and APAAP were repeated for 0.5 hour. The color
reaction was produced using a Neufuchsin (Merck 4041; Merck, Darmstadt, Germany) substrate incubating for 40 minutes. All
incubations were performed at room temperature. Between incubation
steps, slides were washed thoroughly in PBS for 10 minutes. Finally, cytospins were counterstained in diluted hematoxilin and washed with
tap water. Simultaneously, the LRP-positive fibrosarcoma HT1080 DR4
control cell line20 was stained as control for the immunocytochemical assay.
All slides were examined and scored independently by two observers,
blinded to the clinical data. Plasma cells were identified on
morphological criteria. At least 250 plasma cells were evaluated. A
sample was considered to be LRP-positive if 10% of the plasma cells
stained with the LRP-56 antibody and the idiotype matched controls were
indeed negative. These criteria were based on previous experience with
LRP-56 staining in 155 cancer specimens, which indicated that a 10%
cut-off value may distinguish two groups of LRP-expressing
tumors.13,21
Determination of prognostic factors.
The serum B2-microglobulin level was determined by means of
a competitive enzyme immunoassay (Phadezym; Pharmacia, Uppsala, Sweden). The plasma cell labeling index (LI) was measured by the incorporation of bromodeoxyuridine as described
previously.22 Serum levels of lactate dehydrogenase (LDH)
were measured according to standard methods.
Statistical analysis.
Data analysis was performed using the SPSS statistical software package
(SPSS Inc, Chicago, IL).
Prognostic parameters such as age were determined at diagnosis and were
retrospectively assessed for their relationship with LRP expression.
The response rates were compared between LRP and prognostic factors
expression groups. Qualitative variables were analyzed using the
chi-squared test. Multivariate analysis was performed using step-wise
discriminant analysis. Overall survival was measured in months from the
moment of diagnosis, providing 95% confidence intervals. Actuarial
survival curves were estimated using the Kaplan-Meier
method,23 and differences in survival between subgroups
were compared with the log-rank test (Mantel-Cox).24 Also,
the hazard rates for each variable were calculated with the
Cox-regression model using enter and remove limits of 0.05 and 0.1. Hypotheses were evaluated at a significance level of 0.05. Two-sided
statistical tests were used in all analyses.
| |
RESULTS |
Frequency and pattern of LRP expression.
LRP was expressed in 47% (33/70) of bone marrow samples of patients
with newly diagnosed myeloma. In the MP-treated population 47% (17/38)
of patients were LRP positive as compared with 50% (16/32) in the
IDM/HDM-treated population. The staining of the LRP-56 MoAb in the
LRP-positive myeloma cells was invariably cytoplasmatic in the
perinuclear region, in a granular fashion (Fig
1). The intensity of the staining was
generally strong, but variance in staining intensity was too small to
justify objective classification between aspirates. LRP expression in
positive bone marrow samples was heterogeneous, typically showing
LRP-56 immunoreactivity in the majority of myeloma cells (median 50%,
range 10 to 90). There were no samples with LRP expression in less than
10% of the plasma cells. LRP was not expressed in plasma cells of
normal donors (0/3) or patients with MGUS (0/5). In the majority of MM
patients as well as in normal donors and MGUS patients, LRP expression was found in granulocytic marrow components, irrespective of expression on plasma cells.
View larger version (81K):
[in this window]
[in a new window]
View larger version (79K):
[in this window]
[in a new window]
| Fig 1.
Alkaline phosphatase immunocytohistochemical staining
using the MoAb LRP-56 of cytocentrifuged bone marrow cells containing >95% plasma cells of a patient with multiple myeloma. Cytospins were
counterstained in diluted hemotoxiline. LRP immunoreactivity in a
granular fashion in the cytoplasm is present in almost all plasma cells
(A). Isotype control is negative (B).
|
|
Correlation with established prognostic factors.
Using previously defined cut-off levels we studied the distribution of
the plasma cell LI%, serum B2-microglobulin
level, and serum LDH in relation to plasma cell LRP expression. The
cut-off level for LI was 2%,25 for
B2-microglobulin 4 µg/mL,26 and for LDH
300 U/L.26 LRP expression was associated with high LDH
levels at diagnosis (X2, P = .05). LRP did not correlate with serum B2-microglobulin (P = .1), plasma cell LI%
(P = .07), or age (P = .9).
LRP expression and response to melphalan chemotherapy.
The response to chemotherapy consisting of MP or IDM/HDM is summarized
in Table 2; in 38 patients treated with
standard MP the overall response rate was 37% (14/38). There were no
complete remissions obtained with MP. In this group, LRP expression was associated with a poor response to induction treatment. Fifty-two percent (11/21) of the LRP-negative patients achieved a remission as
compared with 18% (3/17) of the patients with LRP-positive myeloma at
diagnosis (X2, P = .027). By univariate analysis, bone marrow
plasma cell LI, serum B2-microglobulin, and serum LDH did not have a significant prognostic value regarding the response to MP
therapy (Table 2).
A remission was achieved in 84% (27/32) of the patients treated with
intensified dose melphalan, including 8 patients who achieved a CR
(25%). No significant difference was found between the response rate
in the LRP-negative patients (88%, 14/16) and the LRP positive
population (81%, 13/16; P = .285). The subgroups of
LRP-positive and LRP-negative IDM/HDM-treated patients showed no
statistically significant differences in distribution of LDH, LI%,
B2-microglobulin, or age. A comparison of responses between the two regimens in LRP-positive patients showed a significant higher
response rate with IDM/HDM as compared with MP (81% v 18%, P < .0001). In LRP-negative patients a better response rate
with IDM/HDM (88% v 52%, P = .006) was also
observed.
Expression of LRP and survival.
Kaplan-Meier survival curves of LRP-positive and LRP-negative patients
are presented in Figures 2-4.An inverse correlation was found between LRP expression and survival
duration. In the complete group, the median survival of LRP-positive
patients was 28 months (95%-Cl: 23 to 33), whereas the median survival
duration of LRP negative patients was 54 months (Cl: 26 to 82;
P < .002; hazard ratio [HR] = 2.9 (1.4-5.7); Table 2, Fig
2). This difference was likely caused by the 38 MP-treated patients who
had a median survival 40 months in LRP-negative (95%-Cl: 41 to 69) and
22 months in LRP-positive patients (95%-Cl: 18 to 26;
P = .0006, HR = 4.1 (1.7-9.8); Table 2, Fig 3). In the
IDM/HDM-treated patients no significant difference in survival between
LRP-positive and LRP-negative patients was observed (median survival 69 months [95%-Cl 14 to 124]) in LRP-negative patients and not reached
in LRP-positive patients (P = .365, HR = 1.7 [0.5-5.9;
Table 2, Fig 4]).
View larger version (13K):
[in this window]
[in a new window]
| Fig 2.
Patients treated with melphalan, either at conventional
dose and combined with prednisone or administered as an intensified (70/140 mg/m2 IV). Probability of survival from the start
of treatment.
|
|
View larger version (13K):
[in this window]
[in a new window]
| Fig 3.
Patients treated with conventional melphalan and
prednisone. Probability of survival from the start of treatment.
|
|
View larger version (13K):
[in this window]
[in a new window]
| Fig 4.
Patients treated with IV intensified melphalan (70/140
mg/m2 IV). Probability of survival from the start of
treatment.
|
|
By univariate analysis LRP (P < .002) was the strongest
adverse prognostic marker for survival in the whole population followed by bone marrow plasma LI, serum B2-microglobulin, and serum
LDH (Table 2). In MP-treated patients high serum LDH
(P = .0001) and LRP expression (P < .0006) both
had an adverse effect on survival (Table 2).
Multivariate analysis showed that in the whole population (50 cases
available for analysis) only LRP expression was an independent prognostic factor (P = .03). In the subgroup of MP-treated
patients (25 cases available) LRP (P = .03) and serum LDH
(P = .0001) remained statistically significant for survival.
In the patients treated with IDM/HDM none of the prognostic factors
affected survival. Age had no prognostic significance for survival by
either univariate or multivariate analysis.
In the subgroup of responding patients we performed statistical
analysis regarding event-free survival (EFS). Within the responding MP-treated patients, the EFS was remarkable shorter in LRP-positive patients. Three LRP-positive patients treated with MP relapsed after 6, 7, and 15 months, respectively (median 7 months, 95%-Cl: 5 to 9),
whereas the EFS of LRP-negative MP-treated patients was median 24 months (n = 11, 95%-Cl; 16 to 32; P < .003). EFS of IDM/HDM-treated LRP-positive patients was median 22 months (n = 14, 95%-Cl: 14 to 30) versus 24 months (n = 13, 95%-Cl: 15 to 33; P = .182) for LRP-negative patients.
| |
DISCUSSION |
Our findings indicate that LRP is widely expressed in untreated MM and
that it is associated with a low probability of response and a shorter
survival in patients treated with a conventional MP regimen. LRP
positivity was found in 47% of the patients with newly diagnosed MM.
This figure is consistent with data indicating the widespread
expression of LRP in untreated human malignancies.13 Multivariate analysis showed that LRP was an adverse prognostic marker
that was independent for serum B2-microglobulin, bone
marrow plasma cell LI, serum LDH, and age. Interestingly, LRP-related resistance to MP may initially be overcome by dose intensification of
melphalan as suggested by the outcome of patients treated with IDM and
HDM.
These observations add proof to the recent in vitro and clinical
studies identifying LRP as an independent predictor for chemoresistance against melphalan. Studies undertaken to assess the in vitro
sensitivity of the RPMI, 8226 human myeloma cell line to several
cytotoxic drugs showed that by exposure to melphalan an MDR subline
emerged, termed 8226 LR5, which is resistant to melphalan and highly
upregulates LRP expression in absence of other MDR proteins (showing a
drug accumulation defect). Also exposure to mitoxantrone resulted in a
highly LRP-positive cell population (8226 MR40), which showed additional resistance to melphalan, again in absence of other MDR-related proteins (W.S. Dalton et al, personal communication, July
1997).
Moreover, in human cancer cell lines derived from 8 cancer types, using
immunocytohistochemical detection methods, a significant correlation
between LRP expression in these cancer types and in vitro sensitivity
to melphalan was found. No correlation was found between the expression
of other MDR-related proteins and melphalan sensitivity.15
These in vitro results are in line with our clinical finding of an
association between LRP expression on myeloma cells in untreated
patients and lack of response to oral melphalan chemotherapy in these
patients.
Further evidence for the relationship of LRP with chemoresistance to
both classical and MDR-related drugs is provided by several recent
clinical studies. In patients with adult myeloid leukemia27 and patients with FIGO stage III/IV ovarian
cancer,21 LRP expression of malignant cells
was significantly correlated with inferior response to chemotherapy,
including cisplatin and alkylating agents, and with shorter overall
survival.
The precise mechanism of LRP-related chemoresistance, however, is still
unsolved. To date the biological function of LRP as a major constituent
of the human vault protein is unknown. A small fraction of vaults are
localized to the nuclear membrane and nuclear pore complexes, raising
the possibility that vaults mediate the bidirectional transport of a
variety of substrates between the nucleus and the
cytoplasm.28 In support of this view, entrapment of drugs
in exocytotic vesicles and decreased nuclear to cytoplasmic drug ratios
were reported in LRP-overexpressing multidrug resistant cells.29,30 Interestingly, melphalan and cisplatin exert
their main cytotoxic effect in the cell nucleus having very similar modes of action on nucleic acids. This makes it tempting to hypothesize that vaults are involved in the nucleo-cytoplasmic exchange of these
drugs.
Our findings cannot exclude that LRP is a pleiotropic marker of
resistance coexpressed with other (MDR-related) drug resistance genes.
In this study we did not assess the expression of other MDR-related
proteins, ie, Pgp and MRP. Therefore, no conclusion can be drawn on the
individual roles of each resistance protein in these MM samples.
However, we and others found that PgP is expressed in very low
frequency (<5%) in untreated MM and has no prognostic value at that
stage.31,32 In contrast, PgP is highly expressed in
VAD-refractory MM,31,33 whereas MRP is not expressed above
background values in the majority of MM samples.34 Moreover, in in vitro experiments and clinical studies MDR and MRP did
not confer resistance to melphalan.15,21
Obviously other nonclassical MDR transport mechanisms of resistance
must be involved in MM, which may explain why resistance occurs in
LRP-negative patients.
An alternate conclusion from the adverse prognostic value of LRP in
patients treated with the MP regimen could be an inverse relation
between LRP expression and the sensitivity of myeloma cells to
corticosteroids. Previous studies have shown that steroid dose
intensity is one of the most important predictors of treatment outcome.
Considering this, the use of prednisone in patients receiving oral
melphalan is an important difference between the treatment groups.
However, recent in vitro studies in acute lymphocytic leukemia using
flow cytometry and a methylthiotetrazole (MTT) assay have shown a lack
of relation between LRP expression and resistance to prednisolone (M.L.
den Boer et al, Department of Paediatrics, Free University Hospital,
Amsterdam, The Netherlands, personal communication, January 1997). In
addition to a potential role in chemoresistance LRP may be associated
with a biologically more aggressive state of MM. This is not only
suggested by the fact that EFS of LRP-positive patients tended to be
shorter but also by the relation between LRP and elevated LDH levels in
untreated disease. LRP did not correlate with serum
B2-microglobulin, LI, or age. High LDH levels in untreated
MM have been related to high tumor mass, unusual clinical features like
extraosseous masses, and hypodiploidy or low RNA content of plasma
cells, possibly reflecting a late stage of myeloma transformation and a
poor clinical outcome.26 Also in our study MP-treated
patients with elevated LDH levels survived significantly shorter. More
detailed studies on the relation of LRP with clinipathological and
cytogenetic parameters in MM are therefore warranted.
Our findings are clinically important because LRP-related resistance to
the MP regimen may be circumvented by dose intensification of
melphalan. LRP-positive patients had a significant better response to
IDM/HDM as compared with MP. The dose-response relation for melphalan
has been widely documented, and dose escalation has been clinically
applied in recent years.3-5 In general, previously untreated patients have superior response rates to intensive regimens as compared with MP, and remissions are of good quality.5
Our results indicate that assessment of the LRP status might identify a
patient population that can initially benefit from dose intensification and in which this regimen could be considered as a first-line treatment
above the MP regimen.
In conclusion, in this study we assessed the expression of LRP in
untreated myeloma and introduce this novel drug resistance-related protein as a prognostic factor for response to the MP regimen and
survival. Moreover, we report that LRP-associated resistance to
melphalan may be circumvented by dose intensification, creating the
possibility to select patients who benefit from these regimens. Further
studies on the expression of LRP and other mechanisms of drug
resistance seem warranted to confirm these results and to clarify the
functional characterization and the biological role of LRP in myeloma
and other tumor types.
| |
FOOTNOTES |
Submitted February 20, 1997;
accepted October 2, 1997.
Address reprint requests to H.M. Lokhorst, MD, PhD,
University Hospital Utrecht, Department of Haematology (G03.647), PO
Box 85500, 3508 GA Utrecht, The Netherlands.
The publication costs of this article were defrayed in part by page
charge payment. This article must therefore be hereby marked
"advertisement" in accordance with 18 U.S.C. section 1734 solely
to indicate this fact.
| |
REFERENCES |
1.
Alexanian R,
Haut A,
Khan AU,
Lane M,
McKelvey EM,
Migliore PH,
Stuckey WY,
Wilson HE:
Treatment for multiple myeloma. Combination chemotherapy with different melphalan dose regimens.
JAMA
208:1680,
1969[Abstract/Free Full Text]
2.
Cooper MR,
Dear K,
McIntyre OR,
Propert KJ,
Kochwa S,
Anderson K,
Coleman M,
Kyle RA,
Prager D,
Kafia S,
Zimmer B:
Single, sequential and multiple alkylating agent chemotherapy for multiple myeloma: A CALBG study.
J Clin Oncol
4:1331,
1986[Abstract/Free Full Text]
3.
Fernberg JO,
Johansson B,
Lewensohn R:
Oral dosage of melphalan and response to treatment in multiple myeloma.
Eur J Cancer
26:393,
1990
4.
Cunningham D,
Paz-Ares L,
Gore ME,
Malpas J,
Hickish T,
Nicolson M,
Meldrum M,
Viner C,
Milan S,
Selby PJ,
Norman A,
Raymond J,
Powles R:
High dose treatment for multiple myeloma: Long-term follow-up data.
J Clin Oncol
12:764,
1994[Abstract]
5.
Lokhorst HM,
Meuwissen OJ,
Verdonck LF,
Dekker AW:
High risk multiple myeloma treated with high dose melphalan.
J Clin Oncol
10:47,
1992[Abstract]
6.
Redwood WR,
Colvin M:
Transport of melphalan by sensitive and resistant L1210 cells.
Cancer Res
40:1144,
1980[Abstract/Free Full Text]
7.
Gupta V,
Singh SV,
Ahmad H,
Medti RD,
Awastithi YC:
Glutathione and Glutathion-S-transferases in a human plasma cell line resistant to melphalan.
Biochem Pharmacol
38:1993,
1989[Medline]
[Order article via Infotrieve]
8.
Hall AG,
Tilby MJ:
Mechanisms of action of, and modes of resistance to, alkylating agents used in the treatment of haematological malignancies.
Blood Rev
6:163,
1992[Medline]
[Order article via Infotrieve]
9.
Goldstein LJ,
Pastan I,
Gottesman MM:
Multidrug resistance in human cancer.
Crit Rev Oncol Hematol
12:243,
1992[Medline]
[Order article via Infotrieve]
10.
Zaman GJ,
Flens MJ,
Van Leusden MR,
Dehaas M,
Mulder HS,
Lankelma J,
Pinedo HM,
Scheper RJ,
Baas F,
Broxterman HJ,
Borst P:
The human multidrug resistance associated protein (MRP) is a plasma membrane drug efflux pump.
Proc Natl Acad Sci USA
91:8822,
1994[Abstract/Free Full Text]
11.
Scheffer GL,
Wijngaard PL,
Flens MJ,
Izquierdo MA,
Slovak ML,
Pinedo HM,
Meijer CJLM,
Clevers HC,
Scheper RJ:
The drug resistance related protein LRP is the human major vault protein.
Nature Med
1:578,
1995[Medline]
[Order article via Infotrieve]
12.
Kedersha NL,
Rome LH:
Isolation and characterization of a novel ribonucleoprotein particle: Large structures contain a single species of small RNA.
J Cell Biol
103:699,
1986[Abstract/Free Full Text]
13.
Izquierdo MA,
Scheffer GL,
Flens MJ,
Giaccone G,
Broxterman HJ,
Meijer CJLM,
Van der Valk P,
Scheper RJ:
Broad distribution of the multidrug-resistance related vault protein LRP in normal human tissue and tumors.
Am J Pathol
148:877,
1996[Abstract]
14.
Scheper RJ,
Broxterman HJ,
Scheffer GL,
Kaaijk P,
Dalton WS,
Van Heijningen THM,
Van Kalken CK,
Slovak ML,
De Vries EGE,
Van der Valk P,
Meijer CJLM,
Pinedo HM:
Overexpression of a M(r) 110,000 vesicular protein in non-P-glycoprotein-mediated drug resistance.
Cancer Res
53:1475,
1993[Abstract/Free Full Text]
15.
Izquierdo MA,
Shoemaker RH,
Flens MJ,
Scheffer GL,
Zaman GJR,
Liu W,
Scheper RJ:
Overlapping phenotypes of multidrug resistance among panels of human cancer cell lines.
Int J Cancer
65:1,
1996[Medline]
[Order article via Infotrieve]
16.
Durie BGM,
Salmon SE:
A clinical staging system for multiple myeloma. Correlation of measured myeloma cell mass with presenting clinical features, response to treatment and survival.
Cancer
36:842,
1975[Medline]
[Order article via Infotrieve]
17. Lokhorst HM, Sonneveld P, Wijermans PW, van Marwijk Kooy M,
Meuwissen OJATh, van Oers MHJ, van der Griend R, Dekker AW:
Intermediate Dose Melphalan (IDM) combined with G-CSF (filgrastim) is
an effective and safe induction therapy for autologous stem cell
transplantation in multiple myeloma. Br J Haematol 92:44, 1996
18. Committee of Chronic Leukemia-Myeloma Task Force National Cancer
Institute: Proposed guidelines for protocol studies. Plasma-cell
Myeloma. Cancer Chemother Rep 4:145, 1973
19.
Cordell JL,
Falini B,
Erber WN,
Ghosh KA,
Zainalabideen A,
MacDonald S,
Pluford KAF,
Stein H,
Mason DY:
Immunoenzymatic labeling of monoclonal antibodies using immune complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP-complexes).
J Histochem Cytochem
32:219,
1984[Abstract]
20.
Slovak ML,
Hoeltge GA,
Dalton WS,
Trent JM:
Pharmacological and biological evidence for differing mechanisms of doxorubicin resistance in two human tumor cell lines.
Cancer Res
48:2793,
1988[Abstract/Free Full Text]
21.
Izquierdo MA,
van der Zee AGJ,
Vermorken JB,
Van der Valk P,
Beliën JAM,
Giaccone G,
Scheffer GL,
Flens MJ,
Pinedo HM,
Kenemans P,
Meijer CJLM,
De Vries EGE,
Scheper RJ:
Drug resistance-associated marker LRP for prediction of response to chemotherapy and prognoses in advanced ovarium carcinoma.
J Natl Cancer Inst
87:1230,
1995[Abstract/Free Full Text]
22.
Lokhorst HM,
Boom SE,
Bast EJEG,
Ballieux RE:
Determination of the plasma cell labeling index with bromodeoxyuridine in a double fluorescence technique.
Br J Haematol
64:271,
1986[Medline]
[Order article via Infotrieve]
23.
Kaplan EL,
Meier P:
Nonparametric estimation from incomplete observations.
J Am Stat Assoc
53:457,
1958
24.
Mantel N:
Evaluation of survival data and two new rank order statistics arising in its considerations.
Cancer Chemother Rep
50:163,
1966[Medline]
[Order article via Infotrieve]
25.
Greipp PR,
Lust JA,
O'Fallon WM,
Katzmann JA,
Witzig TE,
Kyle RA:
Plasma cell labeling index and  2-microglobulin predict survival independent of thymidine kinase and C-reactive protein in multiple myeloma.
Blood
81:3382,
1993[Abstract/Free Full Text]
26.
Durie BGM,
Stock-Novack D,
Salmon SE,
Finley P,
Beckord J,
Crowley J,
Coltman CA:
Prognostic value of pretreatment serum B2-microglobulin in myeloma: A South-west Oncology Group study.
Blood
75:823,
1990[Abstract/Free Full Text]
27.
List A,
Spier CS,
Grogan TM,
Baier M,
Greer JP,
Wolff SN,
Broxterman HJ,
Scheper RJ,
Dalton WS:
Overexpression of the major vault transporter protein LRP predicts treatment outcome in AML.
Blood
87:2464,
1996[Abstract/Free Full Text]
28.
Chugani DC,
Rome LH,
Kedersha NL:
Evidence that vault ribonucleoprotein particles localize to the nuclear pore complex.
J Cell Sci
106:23,
1993[Abstract]
29.
Schuurhuis GJ,
Broxterman HJ,
De Lange JH,
Pinedo HM,
Van Heijningen THM,
Kuiper CM,
Scheffer CM,
Scheper RJ,
Van Kalken CK,
Baak JPA,
Lankelma J:
Early multidrug resistance, defined by changes in intracellular doxorubicin distribution, independent of P-glycoprotein.
Br J Cancer
64:857,
1991[Medline]
[Order article via Infotrieve]
30.
Coley HM,
Amos WB,
Twentyman PR,
Workman P:
Examination by laser scanning confocal fluorescence imaging microscopy of the subcellular localisation of anthracyclines in parent and multidrug resistant cell lines.
Br J Cancer
67:1316,
1993[Medline]
[Order article via Infotrieve]
31.
Grogan TM,
Spier CM,
Salmon SE,
Matzner M,
Rybski J,
Weinstein RS,
Scheper RJ,
Dalton WS:
P-glycoprotein expression in human plasma cell myeloma: Correlation with prior chemotherapy.
Blood
81:490,
1993[Abstract/Free Full Text]
32.
Cornelissen JJ,
Sonneveld P,
Schoester M,
Raaijmakers HGP,
Nieuwenhuis HK,
Dekker AW,
Lokhorst HM:
MDR1-expression and response to vincristine, doxorubicin, and dexamethasone chemotherapy in multiple myeloma refractory to alkylating agents.
J Clin Oncol
12:115,
1994[Abstract]
33.
Sonneveld P,
Schoester M,
de Leeuw K:
Clinical modulation of multidrug resistance in multiple myeloma: Effect of cyclosporine on resistant tumor cells.
J Clin Oncol
13:1584,
1994[Abstract/Free Full Text]
34.
Burger H,
Nooter K,
Zaman GJR,
Sonneveld P,
Van Wingerden KE,
Oostrum RG,
Stoter G:
Expression of the multidrug resistance-associated protein (MRP) in acute and chronic leukemias.
Leukemia
8:990,
1994[Medline]
[Order article via Infotrieve]
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
L. Bouhamyia, S. Chantot-Bastaraud, S. Zaidi, P. Roynard, C. Prengel, J.-F. Bernaudin, and J. Fleury-Feith
Immunolocalization and Cell Expression of Lung Resistance-related Protein (LRP) in Normal and Tumoral Human Respiratory Cells
J. Histochem. Cytochem.,
August 1, 2007;
55(8):
773 - 782.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
U. Stein, K. Jurchott, M. Schlafke, and P. Hohenberger
Expression of Multidrug Resistance Genes MVP, MDR1, and MRP1 Determined Sequentially Before, During, and After Hyperthermic Isolated Limb Perfusion of Soft Tissue Sarcoma and Melanoma Patients
J. Clin. Oncol.,
August 1, 2002;
20(15):
3282 - 3292.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F. Zhan, J. Hardin, B. Kordsmeier, K. Bumm, M. Zheng, E. Tian, R. Sanderson, Y. Yang, C. Wilson, M. Zangari, et al.
Global gene expression profiling of multiple myeloma, monoclonal gammopathy of undetermined significance, and normal bone marrow plasma cells
Blood,
March 1, 2002;
99(5):
1745 - 1757.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. C. Anderson, J. D. Shaughnessy Jr., B. Barlogie, J.-L. Harousseau, and G. D. Roodman
Multiple Myeloma
Hematology,
January 1, 2002;
2002(1):
214 - 240.
[Abstract]
[Full Text]
|
|
|
|
|
|
|
N. Ohno, A. Tani, K. Uozumi, S. Hanada, T. Furukawa, S. Akiba, T. Sumizawa, A. Utsunomiya, T. Arima, and S.-i. Akiyama
Expression of functional lung resistance-related protein predicts poor outcome in adult T-cell leukemia
Blood,
August 15, 2001;
98(4):
1160 - 1165.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Filipits, U. Jaeger, I. Simonitsch, C. Chizzali-Bonfadin, H. Heinzl, and R. Pirker
Clinical Relevance of the Lung Resistance Protein in Diffuse Large B-Cell Lymphomas
Clin. Cancer Res.,
September 1, 2000;
6(9):
3417 - 3423.
[Abstract]
[Full Text]
|
|
|
|
|
|
|
W. S. Dalton and R. J. Scheper
Lung Resistance-Related Protein: Determining Its Role in Multidrug Resistance
J Natl Cancer Inst,
October 6, 1999;
91(19):
1604 - 1605.
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. J. G. Arts, D. Katsaros, E. G. E. de Vries, M. Massobrio, F. Genta, S. Danese, R. Arisio, R. J. Scheper, M. Kool, G. L. Scheffer, et al.
Drug Resistance-associated Markers P-Glycoprotein, Multidrug Resistance-associated Protein 1, Multidrug Resistance-associated Protein 2, and Lung Resistance Protein as Prognostic Factors in Ovarian Carcinoma
Clin. Cancer Res.,
October 1, 1999;
5(10):
2798 - 2805.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Filipits, J. Drach, G. Pohl, J. Schuster, T. Stranzl, J. Ackermann, R. Konigsberg, H. Kaufmann, H. Gisslinger, H. Huber, et al.
Expression of the Lung Resistance Protein Predicts Poor Outcome in Patients with Multiple Myeloma
Clin. Cancer Res.,
September 1, 1999;
5(9):
2426 - 2430.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. A. Shtil, J. G. Turner, J. Durfee, W. S. Dalton, and H. Yu
Cytokine-Based Tumor Cell Vaccine Is Equally Effective Against Parental and Isogenic Multidrug-Resistant Myeloma Cells: The Role of Cytotoxic T Lymphocytes
Blood,
March 15, 1999;
93(6):
1831 - 1837.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
Abstract
Introduction
Abstract