The proto-oncogene c-myb is expressed in sporadic bovine lymphoma, but not in enzootic bovine leukosis.

We examined bovine c-myb gene expression in six samples of sporadic bovine lymphomas (two calf, three thymic and one intermediate) and five of enzootic bovine leukosis. Tumor cells of the sporadic bovine lymphomas were of immature cell lineage (one B lymphoma and five T lymphomas). The c-myb mRNA was expressed in almost all the sporadic bovine lymphomas (except for one thymic form) including a BoCD8 single positive T lymphoma. On the contrary, c-myb was not expressed in mature B lymphomas of enzootic bovine leukosis. The results suggest that c-myb expression is closely associated with tumor cell differentiation of bovine lymphomas.