The expression of C-myb in human metastatic melanoma cell lines and specimens.
The rapidly increasing incidence of malignant melanoma and lack of effective systemic therapy for advanced disease has given rise to the need for new approaches. The suggestion that c-myb may be an important gene in the control of melanoma proliferation prompted the exploration of its expression in several metastatic melanoma cell lines and specimens. Initial Northem hybridization showed undetectable expression of c-myb in the cell lines, although it was very strongly expressed in the K-562 cell line. Therefore, c-myb expression was examined utilizing primers and RT-PCR on the five melanoma cell lines and thirty-two metastatic melanoma specimens. There was very low expression in the two cell lines (UISO Mel-1 and 3) that were nontumorigenic, whereas there was a 10 fold increase in expression in the tumorigenic cell lines. In the metastatic specimens the expression varied by over 100 fold between the lowest and highest specimens. The expression of c-myb in tumor specimens was in general greater than matched normal specimens, save for skin which had moderate expression. In general, there did not appear to be any correlation between the clinical characteristics of the various specimens and the amount of c-myb expression. However, females with lymph node metastases had somewhat lower expression than males. The fact that significant melanoma specimens have altered expression of c-myb, coupled with the previous inhibition of melanoma growth by antisense c-myb, suggests that there may be a potential role for c-myb antisense therapy in the treatment of this tumor.