[Immunohistochemical studies of ras oncogene product p21 in 7,12 dimethylbenz (a) anthracene-induced rat ovarian tumors].

In the present study, ras oncogene product p21 was analyzed immunohistochemically in rat ovarian tumors induced by 7,12 dimethylbenz (a) anthracene (DMBA). 1) After 28-38 (average 35.6) weeks, the tumors -6 adenomas, 30 adenocarcinomas, 3 sarcomas, one mixed müllerian tumor and 2 epidermal cysts--were produced in the rat ovaries. 2) The p21 positive reactions could be seen in the cytoplasm of the tumor cells. The positive rates were as follows: adenomas 83%, adenocarcinomas 57%, sarcomas 67%, mixed müllerian tumors 0%, epidermal cysts 100%, in which the positive reactions were obtained in squamous cells. Both of the serial-allografted tumor and DMBA-OC-1 were positive. 3) The present study showed that the ras oncogene is not a specific gene in ovarian sarcoma or in other tumors. 4) The present study has suggested that the ras oncogene plays a role in tumor genesis including benign tumors, by showing p21 positive in adenomas and epidermal cysts.