Expression of p21 ras protein in human melanoma cell lines.

Samples obtained from six human melanoma cell lines have been tested for the presence of p21 ras oncogene product by Western blotting analysis. The overexpression of p21 was detected in two cell lines out of the six samples. These DNA samples have not been shown to be transformants by transfection assay. Moreover, amplification or rearrangement of DNAs from these cell lines was not found by Southern blotting analysis. Northern blotting analysis, however, detected the expression of Ki-ras gene in RNA extracted from the two cell lines. Thus, it was suggested that the overexpression of p21 might be a result of increased normal mRNA transcript of Ki-ras gene.