p53 expression, p21 expression and the apoptotic index in endometrioid endometrial adenocarcinoma

Although several genetic abnormalities are known to occur in endometrial cancer, including tp53 gene mutation, the pathogenesis of this common malignancy remains poorly defined. We investigated the relationship between overexpression of p53 protein, p21 protein expression and apoptosis in endometrial carcinoma.

Sixteen cases of endometrial carcinoma in which polymerase chain reaction analysis had demonstrated the absence of a tp53 gene mutation were selected on the basis of p53 protein expression; p21 protein expression and the apoptotic index were then determined for each case. The proportion of cells in each case expressing p53 and p21 protein immunoreactivity was compared with the apoptotic index. Overall, no significant correlation was demonstrated between p53 and p21 immunoreactivity, or between either p53 or p21 and the apoptotic index.

Factors other than p53 are involved in the regulation of p21 expression and apoptosis in endometrioid endometrial adenocarcinomas without p53 mutations. Despite the small numbers used in this study, the data suggest a correlation between low levels of p53 immunoreactivity and apoptosis. We postulate that high levels of p53 immunoreactivity may be due to abnormal stabilization of the p53 protein. Follow-up studies are needed with a larger data set.