MLL gene rearrangement, cytogenetic 11q23 abnormalities, and expression of
the NG2 molecule in infant acute myeloid leukemia
JM Hilden, FO Smith, JL Frestedt, R McGlennen, WB Howells, PH Sorensen, DC Arthur, WG Woods, J Buckley, ID Bernstein and JH Kersey
Children's Health Care-St Paul Department of Pediatric Oncology, MN 55102,
USA.
To study prognostic factors in infant acute myeloid leukemia (AML), we
analyzed 44 children treated on Childrens Cancer Group protocols for MLL
gene rearrangement by Southern blot, cytogenetic 11q23 abnormalities, and
reactivity with monoclonal antibody 7.1. This antibody detects the human
homologue of the rat NG2 chondroitin sulfate proteoglycan molecule, which
has previously been reported to be expressed on human melanoma. NG2 has
been found to be expressed on human leukemic blasts but not on other
hematopoietic cells. In childhood AML, NG2 cell surface expression
correlated with poor outcome and with some but not all 11q23
rearrangements. In childhood acute lymphoblastic leukemia, NG2 expression
correlated with poor outcome and with balanced 11q23 translocations. In
this study, 29 of 44 (66%) of infants with AML showed MLL rearrangement
and, as expected, this group had a high incidence of
French-American-British M4/M5 morphology (22/29). Of the cases tested,
35.1% (13/37) were NG2 positive. All (13/13) NG2-positive cases were
rearranged at MLL, whereas only 46% (11/24) of NG2-negative cases had MLL
rearrangement. NG2 expression did not correlate with poor outcome (P =
.31); there was a trend towards a worse outcome with MLL rearrangement (P =
.13). Thus monoclonal antibody 7.1 does not detect all cases of MLL
rearrangement in infant AML.
Volume 89,
Issue 10,
pp. 3801-3805,
05/15/1997
Copyright © 1997 by The American Society of Hematology
