Different H2 haplotypes have a strong influence on oncogene action

The H2 complex has an important role in determining susceptibility to viral and chemical leukemogenesis in inbred mice. This also applies to transplan table leukemias, within the syngeneic sytem. In this respect H2(K) is sensi tive, H2(d) is relatively sensitive, and H2(b) is absolutely resistant to l eukemia induction and transplantation. In our present study we investigated the effect of Cyclophosphamide, (a known chemical leukemogen) on onco/supp ressor gene expression in CBA/Ca mice, very shortly after treatment with ch emical carcinogen without any manifestation of tumour/leukemia symptoms. He re we describe, in a "short-term" experiment, the gene expression of Ha-ras , c-myc and p53 which was similar to the leukemia induction in a "long-term " experiment. H2(K) showed marked elevation in terms of onco/supressor gene expression. H2(b) expression was modest and H2(d) turned out to be more or less silent, The results obtained from a short term gene expression invest igation shows similarity to those obtained earlier from long term leukemia inducing experiments.