Cytogenetic abnormalities in 532 patients with myeloid leukemias and myelodyplastic syndrome. The Czechoslovak MDS Cooperative Group.

A total of 170 patients with chronic myeloid leukemia (CML), 107 in chronic phase (CP) and 63 in blastic phase (BP) of the disease, 187 patients with "de novo" acute myelogenous leukemia (AML) and 175 patients with myelodysplastic syndrome (MDS), 164 patients with primary and 11 with secondary MDS, were cytogenetically examined. All patients with CML were Ph positive, additional chromosomal changes were ascertained in 29% of patients in CP and in 71% of patients in BP. The most frequent chromosomal abnormalities were trisomy 8, additional Ph, (i(17q] and loss of Y chromosome. More favorable course of the disease was observed for group of patients with Ph chromosome as solitary chromosomal abnormality in CP. Acquired chromosomal aberrations were proved in 137 patients with AML (73.3%). Except specific chromosomal changes delineated according to the specific subtype of AML we were concerned with evaluation of nonrandom chromosomal abnormalities, specially those involving chromosome 5 and 7. Numerical and morphological changes of those chromosomes were found in 33 patients (17.6%). In MDS patients abnormal chromosomal clones were found in 68.8% of patients, those involving chromosome 5 and/or 7 in 68 patients (38.8% of all examined). The frequency of these abnormalities in AML does not differ significantly from the results quoted by the other studies. However, in our MDS patients these so called "mutagen-associated" chromosome abnormalities were significantly more frequent than in all studies published so far. Prognostic value of cytogenetic examination was evaluated on the basis of cumulative survival of patients with normal and abnormal chromosomal clones present in bone marrow cells.