Objective: To evaluate the expression of p53, c-erb-B-2, MIB1 and Bcl-2 in normal endometrium, endometriosis, atypical endometriosis and ovarian cancer associated with endometriosis, looking for immunohistochemical markers that may help determine endometriosis with premalignant potential.
Study design: Between 1948 and 1999, 410 epithelial ovarian cancers and 521 cases of endometriosis were surgically treated at Fundación Jiménez Díaz. Pathology reports and slides were reviewed. Four groups were defined: (1) endometriosis/cancer (n=17); (2) atypical endometriosis (n=6); (3) endometriosis (n=17); (4) endometrium (n=7). Tumors and controls were immunostained and evaluated for expression of p53, c-erb-B-2, MIB1 and Bcl-2. Statistical analysis was performed using Chi-square for linear trends, Fisher exact and Kruskal-Wallis tests.
Results: Of the 410 cancers, 17 (4.1%) had associated endometriosis and of the 521 endometriosis, 6 (1.2 %) had atypical changes. Fourteen of 17 (82.4%) cancers associated with endometriosis and all atypical endometriosis had p53 overexpression. Only 2 of 17 (11.8%) endometriosis and none of the endometriums had mutant p53 (P<0.01). We found a trend towards increased expression of MIB1 (0.073) in the cancer and atypical endometriosis groups, and no differences in expression of Bcl-2 or c-erb-B-2. The sensitivity and specificity of p53 as a marker for the diagnosis of atypical endometriosis and cancer associated with endometriosis were 87%; CI 95% (73.2-100%) and 92% (80.6-100%), respectively. When comparing all groups, the mean positive p53 and MIB1 cell count was statistically significant (P=0.01).
Conclusions: Overexpression of p53 in atypical endometriosis and cancer associated with endometriosis is a common finding and may be used to identify endometriosis with premalignant potential.