Studies on four cellular proto-oncogenes and their expression in PCC4 embryonal carcinoma cells: amplification of c-Ki-ras oncogene.

We examined the expression of four cellular proto-oncogenes in two teratocarcinoma cell lines, one undifferentiated and malignant (PCC4), one differentiated and non malignant (PCD1). In this paper we report that transcript levels of c-Ki-ras, c-myc and c-fos are significantly higher in PCC4 cells whereas transcripts of c-Ha-ras are unchanged. Southern blot analysis does not reveal any structural alteration of c-myc and c-fos in PCC4 cells. On the contrary, the c-Ki-ras proto-oncogene is amplified 10 to 20 fold in PCC4 cells.