Leukemic transformation in three patients with polycythemia vera. Analysis of the clinicopathological features and N-ras gene mutation.

: Thirty-three patients were diagnosed as having polycythemia vera (PV) from 1973 to 1993 in our institution. Of these patients, three who had been treated with alkylating agents, progressed to acute non-lymphocytic leukemia (ANLL). Their physical findings and the laboratory data were similar to those patients who did not become leukemic. To investigate the association with leukemic evolution, we examined N-ras oncogene activation in those patients who progressed to acute leukemia. Point mutations in codons 12 and 13 were not always detected, suggesting that the N-ras gene did not influence occurrence of ANLL in our patients.