Impact of neoadjuvant chemotherapy on lymphocytes and co-inhibitory B7-H4 molecule in gastric cancer: low B7-H4 expression associates with favorable prognosis

Little is known on the immune response after neoadjuvant chemotherapy (NACT) in gastric cancer (GC). The present study aimed to investigate the effects of NACT on tumor cells and tumor-infiltrating lymphocytes (TILs) in patients with GC. Expressions of CD4+ and CD8+ TILs and identified co-inhibitory B7-H4 molecule were examined by immunohistochemical staining in GC tissues of 56 patients who received NACT (NACT group) and 46 patients who did not receive NACT (nNACT group). These markers, clinicopathological features, and overall survival (OS) time between both groups were compared. Results showed that the clinicopathological features of patients were not significantly associated with NACT (P > 0.05), but the rate of low expression of B7-H4 (78.6 vs. 47.8 %, P = 0.005) and rate of high expression of CD4+ TILs (58.9 vs. 39.1 %, P = 0.048) and CD8+ TILs (92.9 vs. 56.5 %, P < 0.001) were both significantly higher in NACT group than that in nNACT group. Further, Kaplan–Meier analysis indicated that there was no significant difference in OS time between the groups. However, in NACT group, those with low B7-H4 expression had significantly longer OS (P = 0.031). The study findings suggest that low expression of B7-H4 could serve as a candidate biomarker for predicting response to NACT and could provide favorable prognostic information in GC.