Consecutive chromosomal studies in patients with myelodysplastic syndrome (MDS). Czechoslovak MDS Cooperative Group.

In order to detect a possible relationship between clonal chromosomal abnormalities acquired during the course of the disease and its prognosis in patients with myelodysplastic syndrome (MDS) the authors have performed consecutive analyses in 77 patients with this disease. They were part of the large series of 209 patients cytogenetically examined during the last ten years. According to the cytogenetic findings we have distinguished three groups: 1) sixteen patients who has a normal karyotype in bone marrow cells at the beginning of the investigation and this finding remained unchanged during the course of the disease. Three of them progressed into acute leukemia (AL) without any detectable change in the chromosomal complement of the bone marrow cells; 2) twenty-five patients who had at the beginning of the study, different pathological chromosomal clones in bone marrow cells. There was no chromosomal evolution detectable during the disease; eight of them progressed into acute leukemia; 3) thirty-six patients who had either normal or pathological chromosomal findings at the first examination and in whom further clonal abnormalities had developed during the course of the disease. Twelve of them progressed into acute leukemia. Two to nine cytogenetic examinations were successfully performed with a mean of three studies per patient. The results confirmed strictly individual development of chromosomal abnormalities during the course of the disease, with an unfavorable prognosis for the patients with complex chromosomal changes. Three patients with del 7q had very poor prognosis with rapid progression of the disease. Two cases with the same acquired abnormalities (del 20q, +8, -22) transformed into acute leukemia within the period of 36 months from the onset of the disease.