Human chronic lymphocytic leukemia cells regularly express mRNAs of the protooncogenes lck and c-fgr.

Protooncogenes, the cellular homologues of transforming retroviral oncogenes, have been suggested to participate in malignant transformation of various cell types. The role activated protooncogenes might play in chronic lymphocytic leukemia (CLL) is not yet clear. We investigated the expression of the protooncogenes lck and c-fgr encoding two protein tyrosine kinases by Northern-blot analysis in 21 patients with B-CLL and transcripts of both genes were detected in all cases. In contrast to CLL B cells, normal B cells from peripheral blood of a healthy donor separated by magnetic sorting did not express c-fgr and lck. The results suggest a possible role for these two protooncogenes of the src family in the activation and/or transformation of human B lymphocytes.