Immunohistochemical analysis of ras oncogene product p21 in human endometrial carcinoma

Monoclonal antibody rp-28 directed against the ras gene product p21 has been used to evaluate ras p21 expression in endometrial lesions. Endometrial cancer showed a variable reactivity according to histological type: in well differentiated adenocarcinoma 63% were positive (12/19); in moderately differentiated adenocarcinoma 53% were positive (8/15); in poorly differentiated adenocarcinoma 40% were positive (2/5). The staining intensity of ras p21 seemed to be stronger in the more differentiated types of endometrial carcinoma. In endometrial carcinoma with premenopausal women, 27% were positive (3/11), and with postmenopausal women 71% were positive (20/28). The difference between premenopausal and postmenopausal groups was statistically significant (Mantel-Haenszel procedure, M-H chi 2 = 6.765, P < 0.01). The results suggest the existence of different carcinogenetic mechanisms in these two groups of endometrial cancer.