Comparison of ras activation in prostate carcinoma in Japanese and American men

Comparative studies of point mutations in K-, N-, and H-ras oncogenes were performed on prostate carcinoma from Japanese and American patients to clarify the racial difference.We probed for mutations in 70 Japanese and 31 American specimens using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis and immunohistochemistry for ras p21.Within the 70 Japanese specimens, eight mutations in codon 12 of K-ras (five GGT--GTT transversions and three CGT--GAT transitions) and one mutation in codon 12 of the N-ras gene (a GGT--GTT transversion) were confirmed, whereas the American samples yielded only one definable mutation, a GGT--GAT transition, in codon 12 of K-ras.The frequency of ras gene mutations in clinical carcinoma in Japanese men was higher than that in American men. It is suggested that there may be fundamental differences in the etiology of prostate carcinoma in Japan and the United States, perhaps based on genetics and/or environmental factors.