Evaluation of PA-MSHA vaccine on the prophylaxis of post-operative intraperitoneal recurrence and metastasis in advanced gastric cancer LING Wei, LIU Hua, CAO Hui, et al. Department of General Surgery, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China Corresponding author ：LIU Hua , E-mail: housman111@yahoo.com.cn Abstract Objective To evaluate the killing effect by PA-MSHA vaccine on gastric cancer cells in vitro and its effect on the prophylaxis of post-operative intraperitoneal recurrence and metastasis in advanced gastric cancer. Methods MTT method was used to observe the inhibition and killing effect by PA-MSHA vaccine on gastric cancer cell strain MKN45 between January 2005 and December 2007 at Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. Specific combination and inhibition of cell proliferation were observed by transmission electron microscopy. Sixty cases of advanced gastric cancer T3M0 were selected into the study which were randomly separated into two groups: PA-MSHA group and control group. It observed side effects, effect on the patients’immune function and intraperitoneal recurrence or metastasis. Results PA-MSHA vaccine could specifically combine and penetrate into the gastric cancer cell strain MKN45 so as to inhibit its proliferation and the killing effect was in direct proportion to its dose. The side effect of PA-MSHA vaccine was comparatively limited. In PA-MSHA group, the cellular immune function was strengthened and intraperitoneal recurrence or metastasis decreased significantly. Conclusion PA-MSHA vaccine has dose-dependent killing effect on gastric cancer cell strain MKN45 by specific combination. It is safe and feasible which can strengthen the cellular immune function and reduce intraperitoneal recurrence or metastasis in advanced gastric cancer.