CYTOGENETIC STUDY OF 50 DE-NOVO CASES OF ANLL FROM ARGENTINA

Background and methods. Consistent and specific chromosomal aberration s have been observed in an increasing number of neoplasias. In the pre sent report, we describe the cytogenetic findings from 50 cases of de novo ANLL in Argentina, South America, studied at diagnosis. In additi on, their relation with the FAB classification is analyzed. Children w ith Down's syndrome and secondary ANLL were excluded from this analysi s. Results and conclusions. Out of 50 banded cases studied, 11 (22%) h ad normal karyotype, while the remaining 39 (78%) presented abnormal m etaphases with structural alterations in the majority of them. Chromos omes 7 and 22 were most frequently involved in numerical alterations i n children, while chromosomes 6, 8, 14 and 16 were the ones most often involved in adults. Consistent chromosome rearrangements were observe d and they were linked to specific cytomorphologic subsets. The transl ocations t(8;21) and t(15;17) were seen only in M2 and M3, respectivel y. The inversion of chromosome 16, inv(l6), was a typical finding in M 4, but was not restricted to this subtype. Translocation t(2;3) was ob served in three cases, all M4, each with a variable chromosome pattern . These results are in accordance with cytogenetic findings in Western