Immunohistochemical Analysis of PGC-1α and ERRα Expression Reveals Their Clinical Significance in Human Ovarian Cancer

Purpose: Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) and estrogen-related receptor alpha (ERR alpha) play a vital role in various human cancers. The purpose of this study was to investigate whether the PGC-1 alpha/ERR alpha axis could serve as an effective prognostic marker in ovarian cancer (OC). Patients and Methods: We investigated the expression of both PGC-1 alpha and ERR alpha in 42 ovarian cancer and 31 noncancerous ovarian samples by immunohistochemistry (IHC). The relationship between the expression of PGC-1 alpha and ERR alpha in OC and the clinical characteristics of patients was evaluated. In addition, data from the Human Protein Atlas (HPA) database were collected to validate the prognostic significance of PGC-1 alpha and ERR alpha mRNA expression in OC. Results: PGC-1 alpha and ERR alpha showed notably higher expression in OC tissues than in noncancerous tissues (P=0.0059, P=0.002). Moreover, in patients with OC, high ERR alpha and PGC-1 alpha/ERR alpha expression significantly correlated with tumor differentiation (P=0.027; P=0.04), lymph node status (P=0.023; P=0.021), CA125 (P=0.036; P=0.021), and HE4 (P=0.021; P=0.05), while high PGC-1 alpha expression was only significantly associated with tumor differentiation (P=0.029). The combined analysis of high PGC-1 alpha and ERR alpha expression revealed a tendency towards poor cancer-specific survival (P=0.1276). Conclusion: PGC-1 alpha and ERRa are overexpressed in OC and might be significant prognostic factors for this cancer.