Abstract
BACKGROUND
The nucleotide excision repair (NER) proteins repair DNA adducts due to xenobiotics and cancer chemotherapy. The authors hypothesized that expression of the NER protein xeroderma pigmentosum A (XPA) would be reduced in a clinically significant fashion in metastatic ovarian carcinoma.
METHODS
Malignant effusion specimens were studied so that there was a uniform metastatic ovarian carcinoma population for study. XPA protein expression was analyzed by immunocytochemistry in 142 effusion specimens (109 peritoneal specimens, 33 pleural specimens) from 125 patients. Specimens were obtained at diagnosis (n = 76), and at disease recurrence (n = 66). Patients in the latter group received platinumβbased chemotherapy.
RESULTS
XPA was expressed in cancer cells in 136 of the 142 (96%) effusion specimens. Strongest expression occurred in leukocytes and reactive mesothelial cells. XPA expression did not correlate with treatment status, effusion site, International Federation of Gynecology and Obstetrics stage, histologic grade, or the extent of residual disease. More effusion tumor cells from patients with a complete response to chemotherapy expressed XPA compared with those with a partial or no response (P = 0.03, Ο^2^ test). Patients with recurrent disease with XPA expressed in > 25% of tumor cells had better progressionβfree survival (PFS) by univariate analysis (median = 0 vs. 11 months, P < 0.001; 95% confidence interval [CI], 1β5, 8β14) and overall survival (OS; median = 24 vs. 34 months, P = 0.04; 95% CI, 17β31, 24β44). XPA was the only predictor of PFS outcome by multivariate analysis (P = 0.03).
CONCLUSIONS
The results of the current study showed that XPA was widely expressed in metastatic ovarian carcinoma effusion specimens and in the cells of the effusion microenvironment. Paradoxically, XPA expression was associated with better response to chemotherapy and predicted better PFS and OS. Cancer 2005. Published 2005 by the American Cancer Society.