Chromosome analysis of 63 cases of secondary nonlymphoid blood disorders: a cooperative study. Groupe Francais de Cytogénétique Hématologique.

A cooperative study of secondary nonlymphoid blood disorders [dysmyelopoietic syndrome and acute nonlymphoblastic leukemia (ANLL)] was carried out on 63 patients, 8 after professional exposure to carcinogenic agents and 55 following exposure to therapeutical hazards. Clonal chromosome abnormalities were observed in 56 cases (88.9%). The most common abnormalities were hypodiploidy and structural defects. The chromosomes most often involved were #7, #5, and #17. Monosomy 7 was seen more often following malignant lymphoma than after cancer, whereas monosomy 17 seemed more common in patients formerly exposed to professional hazards. Cytogenetic "variation" is often accompanied by cytologic "variation," which could explain the high proportion of ANLL cases that are difficult to classify into the FAB system. A correlation was found between complete monosomy 7 and the presence of micromegakaryocytes and/or macroplatelets .