Chromosomal findings and their correlation to prognosis in acute lymphocytic leukemia.

Sixteen of the 17 patients with acute lymphocytic leukemia (ALL) were revealed to have chromosome abnormalities in their leukemic cells. Of nine children, six had modal chromosome numbers between 50 and 59; these patients and one additional patient with a pseudodiploid karyotype have achieved and retained a complete remission. The only patient without chromosome abnormalities achieved a remission, but had a relapse and died. The only child who expired without achieving a remission had 47 chromosomes in his leukemic cells. Of eight adults, none had the hyperdiploidy seen in the children. The four with hypo-or pseudodiploidy failed to achieve a complete remission. One patient had 47 chromosomes in his leukemic cells, and this patient and the remaining three, all with ploidy abnormalities, achieved a complete remission, but a relapse occurred and they died. The chromosomal abnormalities were very extensive in most cases, many patients having marker chromosomes of an unknown origin. Four patients clearly exhibited karyotypic evolution when they relapsed. The patients with hyperdiploidy had a better prognosis, and those with pseudodiploidy had a poorer prognosis. The role of individual chromosome aberrations, however, remains to be elucidated.