Comparing ERCC1 protein expression, mRNA levels, and genotype in squamous cell carcinomas of the head and neck treated with concurrent chemoradiation stratified by HPV status.

Abstract

Previous studies examining excision repair cross-complementation group 1 (ERCC1) in squamous cell carcinoma of the head and neck (SCCHN) have not compared methods of ERCC1 testing nor been stratified by human papillomavirus (HPV) status. ERCC1 protein expression, mRNA, and genotype were retrospectively evaluated from pretreatment biopsies in 55 patients with SCCHN treated with chemoradiation. In all, 50% of patients had high ERCC1 protein expression, 28.2% had low mRNA levels, and genotype frequencies were C/C = 17.1%, C/T = 43.9%, and T/T = 39.0%. No correlations were found among protein expression, mRNA, or genotype. With a median follow-up of 54 months, the 5-year overall survival was 57.7%. After adjusting for known prognostic factors, ERCC1 protein level and genotype resulted in hazard ratios indicating an increased risk of death of 4.4-fold (p = .004) and 4.2-fold (p = .044), respectively. An exploratory analysis suggested a differential prognostic effect in HPV-negative SCCHN. ERCC1 protein expression using the FL297 antibody warrants further study as a potential prognostic marker in SCCHN.