H‐ras‐1 polymorphism in leukemia

We have examined leukocyte DNAs obtained from 21 patients with various types of leukemia for the Sacl polymorphism of H‐ras‐1. The patients included ten with B‐lineage leukemia, two with T‐cell leukemia, and nine with acute myelogenous leukemia. Using a genomic probe for H‐ras‐1 in Southern hybridizations, we found that 78% of the DNA from leukemias of myeloid origin were heterozygous. In contrast, only three of ten B‐cell‐derived leukemias showed heterozygosity. This difference in the number of heterozygotes vs. homozygotes in the two patient samples studied is statistically significant (P = 0.04 by Fisher's exact test). These results suggest the possibility that the H‐ras‐1 allelic pattern that is associated with acute myelogenous leukemia is distinct from that found in B‐cell‐derived malignancies.