Association between ERCC1 and XPA expression and polymorphisms and the response to cisplatin in patients with non-seminomatous testicular germ cell tumors.

4555 Background: Cisplatin-based chemotherapy cures over 80% of testicular germ cell tumors (TGCTs); nucleotide-excision repair (NER) modifies the sensitivity to cisplatin. In this work we explored the association between NER-proteins and their polymorphisms (SNPs) with cisplatin-sensitivity (CPS) and overall survival (OS) of patients with advanced non-seminomatous (ns)-TGCTs treated with bleomycin-etoposide-cisplatin (BEP). Methods: ERCC1, XPA-expression and gammaH2AX-presence, were tested in cisplatin-treated cancer cell lines. ERCC1 and XPA-expression were also analyzed in ns-TGCTs by qPCR. Immunohistochemistry was performed to detect ERCC1 protein in ns-TGCTs specimens. The SNPs were genotyped by PCR-RFLPs technique. Results: High basal ERCC1-expression was observed in non-CPS cancer cell lines; ERCC1-expression augmented further, as well as gammaH2AX, after cisplatin-treatment. Basal ERCC1 expression increases in the non-CPS patients in Mexican and Peruvian populations compared to CPS patients (p<0.001; p=0.002). XPAexpression levels weren’t different. These polymorphisms weren’t associated with CPS or OS. ERCC1-positive immunostaining was observed in 30/108 patients (27.8%). From 76 patients that were CPS, 59 (77.6%) were ERCC1-negative, compared with 17 (22.4%) that were ERCC1-positive (p=0.05). 5-year OS probability was smaller for those patients ERCC1-positive and non-CPS (15.38%) than tumor ERCC1-negative and CPS (89.3%) (p<0.001). Using the Cox Model, adjusted on the prognosis groups, the hazard ratio (HR) of death in patients with ERCC1-negative and non-CPS was >14.43 and in patients ERCC1-positive and non-CPS the HR was >11.86 (p<0.001). Conclusions: High-levels of ERCC1-expression and ERCC1-protein are associated with non-CPS, suggesting the use of ERCC1 as a potential indicator of response to cisplatin-based chemotherapy and the prognosis in patients with ns-TGCTs. Moreover, it’s important to identify patients potentially non-CPS in order to diminish the toxicity of cisplatin and improved quality of life avoiding adverse effects due to this agent. Work supported by CONACYT 83959 and PAPIIT IN213311-3.