Expression of p53 in epithelial carcinoma of the ovary after chemotherapy

To compare the expression of p53 protein before and after chemotherapy in epithelial carcinoma of the ovary.

Thirty patients were identified during a 10-year period with both their primary surgery and laparotomy after chemotherapy at the same institution. Tissue was processed from paraffin blocks, exposed to an antihuman p53 monoclonal antibody, then stained. Patient records were reviewed for survival data.

Twelve of 30 (40%) patients' tissue initially stained positive for p53. Seventeen of 30 (56.7%) were negative, and one (3.3%) was mixed. Eight of 12 (66.7%) initially positive remained so after chemotherapy, 2 converted to negative, and 2 converted to mixed expression. One patient with mixed expression converted to positive after chemotherapy. Seventeen tissues initially negative remained unchanged.

Chemotherapy did not permanently alter the expression of p53 detected by immunohistochemical staining in the majority (83.3%) of patients with epithelial ovarian cancer; 16.7% (all initially over-expressing p53) did show some decrease. This may have been due to deactivation of the mutated p53 gene, spontaneous mutation, selective growth within a heterogeneous population or alteration of p53 protein.