SERUM ANTIBODIES AGAINST GroEL AS AN ADDITIONAL RISK BIOMARKER OF BIOCHEMICAL RECURRENCE AFTER RADICAL PROSTATECTOMY.

Abstract

Thelevel of heat shock protein 60 (Hsp60) is elevated in tumor cells compared with normal prostate epithelium. Hsp60is involved in tumor growth, invasion, and metastasis and is considered as a biomarker for cancer diagnosis and prognosis. To study thelevel of antibodies against prokaryotic homolog of human Hsp60 (GroEL) in prostate cancer (PCa) patients as an additional risk marker for theprediction of biochemical recurrence after radical prostatectomy (RP). A total of 55patients with localized and locally advanced PCa, who had undergone RP between July 2013and May 2014were enrolled. Level of antibodies to GroEL and human Hsp60was determined by enzyme-linked immunosorbent assay before surgery. Serum samples of blood donors with low reactivity to GroEL and human Hsp60were used as controls. Therelationship between IgG antibodies against bacterial Hsp60and human Hsp60and clinicopathological features were analyzed. Thebiochemical recurrence (BCR) free survival rate was estimated by theKaplan - Meier method. Theunivariate and multivariate Cox regression models were used to evaluate therisk factors of BCR-free survival rate. There were significant differences in anti-GroEL IgG levels between control and PCa patients while no significant differences in anti-human Hsp60IgG levels between control and PCa patients were detected. During thefollow-up period, 40/55 (72.7%) patients developed BCR. Thetime from surgery to BCR was from 18to 72months. Elevated IgG antibodies against bacterial Hsp60in patients who had undergone RP were associated with early occurrence of biochemical relapse and lower 5-year BCR-free survival rate respectively (p < 0.001). Themultivariate analysis indicated that IgG to GroEL (hazard ratio = 2.465; 95% confidence interval: 1.311-4.634, p < 0.05) could be independent prognostic factor in thepatients who had developed BCR. Elevated levels of IgG antibodies against GroEL before surgery can predict early occurrence of BCR after RP and can serve as an additional independent risk biomarker of a BCR after RP.