Abstract LB-229: Mesothelin expression is a predict factor for peritoneal recurrence in gastric cancer

Abstract

Abstract Background: Mesothelin is overexpressed in many solid tumors. Recent studies showed that mesothelin expression is associated with poor outcome in several malignant tumors and it may play a role of cancer cell proliferation, local invasion and metastasis. Clinical trials of mesothelin-targeted immunotherapies are currently in progress. However, the correlation between mesothelin expression and prognosis of gastric cancer is still conflicting. Patients and Methods: Mesothelin expression in tumour cells were immunohistochemically evaluated in 964 advanced gastric cancer patients, and their associations with clinical outcome were analysed. The prediction model for recurrence was developed by cox proportional hazard models. Results: High mesothelin expression was observed in 49.6% and significantly associated with a high stage (P = 0.022) and the presence of recurrence with peritoneal carcinomatosis (P = 0.002). In univariate survival analysis, high mesothelin expression was significantly associated with shorter recurrent-free survival (RFS) (P=0.003) and overall survival (OS) (P=0.006). Multivariate survival analysis revealed that high mesothelin expression was independently associated with poor RFS and OS (P=0.001; P=0.002, respectively) in addition to stage, lymphovascular invasion and Lauren classification (all, P<0.001). In multivariate analysis for recurrence with peritoneal carcinomatosis, high mesothelin expression was also independent prognostic factors in all advanced gastric cancer patients (P<0.001) and in intestinal (P=0.017) and diffuse/mixed type (P=0.005) subgroups. The overall discrimination ability of prediction model for recurrence, the model with mesothelin was better than model without mesothelin. Conclusions: High mesothelin expression was correlated with poor outcome. And, mesothelin expression, along with Lauren classification was meaningful predict factor for peritoneal recurrence. Citation Format: Su-Jin Shin, Hyunki Kim, Yoon Young Choi, Sejung Park, Chung Mo Nam, Hyun Cheol Chung. Mesothelin expression is a predict factor for peritoneal recurrence in gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-229.