Seventy testicular germ cell tumors were analyzed at the DNA and RNA levels for the c-kit, hst-1, and int-2 oncogenes using Northern and Southern blot analyses, respectively. There were significant differences in oncogene expression between seminomas and nonseminomas with c-kit being expressed in 24 of 30 (80%) seminomas but in only 3 of 40 (7%) nonseminomatous tumors (P = 0.0001, x2 test) and hst-1 being expressed in 24 of 38 (63%) nonseminomas but only 1 of 24 (4%) of seminomas (P= 0.0001, x2 test), demonstrating an inverse relationship in the expression pattern of these 2 oncogenes in human testicular germ cell tumors. A significant association between tumor stage and hst-1 expression in the nonseminoma group was found (P = 0.0002, x2 test). No gross alterations in the c-kit, hst-1, and int-2 loci were found at the DNA level and no int-2 mRNA expression was detected in any of the germ cell tumors examined.
This work was supported by USPHS Grant CA 36827. T.S. is supported by grants from Deutscher Akademischer Austauschdienst (312 402 698 9) and Deutsche Forschungsgemeinschaft (Str. 270/2-1). D.J.S. is supported by American Cancer Society Grant FRA 323.