Cytogenetics of secondary myelodysplasia (sMDS) and acute nonlymphocvtic leukemia (sANLL)

Abstract

76 cases of secondary myelodysplasia (sMDS) and acute nonlymphocytic leukemia (sANLL) were cytogenetically analyzed. Among the 36 sMDS patients, 13 (36%) had only normal karyotypes whereas 23 (64%) displayed clonal chromosomal abnormalities. The most common aberrations were −7, 5q-, −5, and +8. In 10 patients (43% of the cytogenetically aberrant cases), clones with only one anomaly, mostly 5q −or − 7, were found. Of the 40 sANLL patients, normal karyotypes were detected in 10 (25%). Among the 30 (75%) abnormal cases, the most frequent aberrations were −7, −5, +8, 7q-, − 17, and +21. 12 patients (40%) had clones with single abnormalities, most often − 7. In 4 sANLL patients cytogenetically unrelated clones were detected. A survey of all previously published secondary hematologic neoplasias reveals that the most frequent abnormalities in sMDS are −7 (41%), 5q- (28%), and − 5 (11x), followed by der(21q), + 8, 7q-, der(12p), t(1;7), − 12, − 17, der(17p), der(3p), der(6p), and − 18. Clones with single aberrations have been found in 45 % of the cases and cytogenetically unrelated clones have been described in 6%. The most common abnormalities in sANLL are −7 (38%), 5q- (17%), −5 (15%), +8 (13%), and − 17 (llx), followed by der(3q), der(11q), der(12p), −21, 7q-, − 18, der(3p), der(17p), +21, der(21q), der(6p), and − 16. 38% of the sANLL patients have had clones with only one aberration and 3% have had unrelated clones. The frequencies of these nonrandom abnormalities in sMDS and sANLL are thus remarkably similar - the only exception appears to be 5q -, which is more common in sMDS. Also the mean number of abnormalities per case is similar − 5.3 in sMDS and 5.6 in sANLL. When the incidences of characteristic cytogenetic abnormalities were correlated with the type of previous therapy, − 7 was found to be more frequent in sMDS and sANLL patients who had been exposed to chemotherapy whereas 5q -was associated with previous exposure to ionizing radiation in sMDS patients.