A group of previously not recognized cytogenetic abnormalities in myeloid hematological malignancies

We have identified a group of previously not reported chromosome abnormalit ies related to myeloid hematological malignancies. Cases 1 and 2 were obser ved to have an additional i(4)(p10) as the sole anomaly with similar clinic al features of myeloid disorders; that is, acute nonlymphocytic leukemia (A NLL-M2) and myelodysplastic syndrome (MDS)-refractory anemia with an excess of blasts in transformation, respectively Fluorescence in situ hybridizati on studies with the use of a 4p-specific microdissection probe further conf irmed the presence of an i(4)(p10) in these patients. Case 3 was diagnosed with ANLL-MI and had an additional i(8)(p10) as the only change, also confi rmed by a whole-chromosome painting procedure. In cases 4-6, deletions of 1 8q at breakpoints q12, q23, and q21 were identified as the sole anomaly in a myeloproliferative disorder (MPD), MPD, and MDS, respectively. X-autosome translocations other than t(x;10)(p11;p11) and t(X;11)(q13;q23) have not b een reported as recurrent or primary changes in hematological disorders. In the present study, a t(X;9)(q26;q22) and t(X;5)(q13;q33) as the sole anoma ly were found in cases 7 and 8, respectively. Both cases had the same diagn osis of MDS. Considering that trisomies 4 (+4) and 8 (+8) are common anomal ies in MDS and ANLL, our findings strongly indicate that amplification of g enes on 4p and 8p, but not on 4q and 8q, may play a crucial role in the pat hogenesis of MDS and ANLL. In addition, genes on 18q12 similar to 23 and on Xq13 similar to 26 may be involved in the pathogenesis of myeloid disorder s. (C) Elsevier Science Inc., 1999. All rights reserved.