Markers of chemoresistance in ovarian carcinomas: an immunohistochemical study of 86 cases.

Markers of chemoresistance have been rarely investigated in human ovarian cancer. This study evaluates the clinical value in ovarian cancer of metallothionein (MT), heat-shock protein-27 (HSP-27) and glutathione-S-transferase pi and alpha (GST pi, GST alpha), recognized for their relation with drug resistance in vitro. The expression of these markers was evaluated by immunohistochemistry on paraffin-embedded tumor specimens from 86 patients with ovarian carcinomas diagnosed between 1977 and 1990 who received chemotherapy. Response to chemotherapy was evaluated using well-defined criteria. Marker expression was evaluated on a section of the primary tumor (81 cases) and, when available, on a section of tumor following chemotherapy (48 cases). MT was expressed in 38.3% of primary tumors unexposed to chemotherapy, HSP-27 in 50.6%, GST pi in 37%, and GST alpha in 50.6%. The expression of all four markers did not help to predict chemoresistance. The concordance between marker expression by the tumor before and after chemotherapy was weak (concordance, 51.2%-70.7%). Immunostaining was not associated (p > 0.1) with any prognostic factor such as stage, residual tumor after surgery and grade. Ovarian cancer is a highly heterogeneous neoplasm and the expression of markers of chemoresistance reflects this heterogeneity. Our data suggest that chemoresistance is more likely multifactorial and confirms the complexity of the in vivo model.