P53-EXPRESSION IN NEOPLASMS OF THE UTERINE CORPUS

It has been recognized that mutations in tumor suppressor genes may have an important oncogenic role. Although abnormalities of the p53 tumor suppressor gene have been reported in tumors from various organ systems, p53 expression has not been studied in neoplasms of the uterine corpus. Using a monoclonal antibody to the p53 product, frozen sections of 56 uterine tumors (40 endometrioid endometrial adenocarcinomas, 7 serous endometrial carcinomas, 4 mixed Mullerian tumors, 2 endometrial stromal sarcomas, 1 leiomyosarcoma, 2 leiomyomas) and 2 normal endometria were stained using the immunoperoxidase technique. Staining was evaluated by light microscopic examination; in carcinomas with strong/diffuse reactivity, evaluation was by digitized image analysis. p53 staining of adenocarcinomas was compared statistically to the histologic type, grade, surgical stage, and clinical follow-up. Specific staining was present in the nucleus of malignant tumor cells only. Benign cells did not stain. Strong/diffuse staining was seen in 14 adenocarcinomas and in 2 mixed Mullerian tumors. Weak/focal staining was observed in 14 adenocarcinomas. Serous carcinomas showed strong positivity more frequently than endometrioid endometrial carcinomas. Staining patterns correlated with histologic grade and stage. Image analysis of immunostained p53 correlated with type of adenocarcinoma, but not with grade or stage in the cases measured. p53 was expressed strongly in tumors of five of eight patients who died of adenocarcinoma but in none of five patients with no evidence of disease and a minimum follow-up of 24 months. In addition, 3 of 12 patients with persistent or recurrent disease showed tumors that strongly expressed p53. It is concluded that abnormal expression of p53 occurs frequently in malignant uterine tumors. Strong immunoperoxidase staining for p53 is associated with serous papillary histologic type and with poor prognosis in endometrial carcinomas.