27. OPLAH PROTEIN EXPRESSION STRATIFIES THE PROGNOSIS OF PATIENTS WITH SQUAMOUS CELL CARCINOMA OF THE ESOPHAGUS

Abstract Background Squamous cell carcinoma (SCC) is one of the major subtypes of esophageal carcinoma, and accounts for up to 90% of esophageal carcinoma cases in eastern Asia and eastern and southern Africa and 50% in Western countries. The 5-year overall survival rate of ESCC patients who undergo curative treatment remains below 40%. The elucidation of molecular biomarkers could be of clinical importance both as prognostic factors besides the established clinical staging and as potential targets for treatment. We aimed to detect and validate the prognosticators of esophageal squamous cell carcinoma in patients who underwent radical esophagectomy. Methods We identified OPLAH as one of the differentially expressed genes between esophageal squamous cell carcinoma (ESCC) tissue and normal esophageal mucosa whose expression changes were significantly associated with a patient prognosis using The Cancer Genome Atlas data. The OPLAH protein expression in ESCC tissue and serum OPLAH protein concentrations were evaluated and analyzed for their association with clinicopathological factors. Results OPLAH mRNA was significantly overexpressed in ESCC tissue compared to normal esophageal mucosa, and patients with high OPLAH mRNA expression had a significantly poorer prognosis according to The Cancer Genome Atlas data. The high staining intensity of OPLAH protein in ESCC tissue clearly stratified patient prognosis. According to the multivariable analysis, high OPLAH protein expression was an independent prognostic factor for survival after surgery. Pre-neoadjuvant chemotherapy serum OPLAH protein concentrations were significantly associated with clinical tumor depth and node positivity and, consequently, with advanced clinical stage. The serum OPLAH protein concentration was significantly decreased by neoadjuvant chemotherapy. Conclusions OPLAH may serve as a useful prognosticator for ESCC patients.