The prognostic significance of p53 tumor suppressor gene alterations in ovarian carcinoma.

BACKGROUND

The prognostic significance and nature of p53 dysfunction in ovarian carcinoma is unclear. The relation between p53 overexpression, p53 mutations, and their effects on overall survival in primary ovarian carcinoma is explored.

METHODS

Tumor specimens from 171 consecutive epithelial ovarian carcinomas were examined for overexpression of p53 protein with DO7 antibody. P53 mutations were determined by direct sequencing. The influences of conventional histopathologic prognostic factors and various p53 molecular alterations on overall survival were assessed.

RESULTS

Overall, 48.5% and 57.3% of the samples showed p53 overexpression and p53 mutation, respectively. Although neither p53 overexpression nor the mere presence of a p53 mutation impacted overall survival, the combination did prognosticate survival both in univariate and multivariate models. The authors' results suggest 4 mechanisms that may affect p53 dysfunction in nearly 100% of advanced stage ovarian carcinomas. These include null mutation, nonresponsive p53 (wild-type [wt] p53 sequence, DO7 negative), sequestration (wt p53 sequence, DO7 positive), and missense mutation. Median survival for these groups that constitute sequentially 21.3%, 20.5%, 12.3%, and 45.9% of the 122 Stage III or IV (International Federation of Gynecology and Obstetrics) cancers was 1.49, 1.31, 3.09, and 3.6 years, respectively. The nonresponsive p53 and null sequence tumors grouped together as functionally null convey the worst prognosis relative to missense mutations in a univariate model (P = 0.006). Functionally null p53 (P = 0.002), stage (P = 0.008), and optimal cytoreduction (P = 0.008) were independent prognostic factors by multivariate analysis.

CONCLUSIONS

Sequestration of wt p53 is unique to advanced stage ovarian carcinoma. Functionally null p53 represents an independent molecular predictor of compromised survival.