High LIMP2 expression serves as a predictor for improved clinical outcomes in gastric cancer patients

Lysosomal integral membrane protein-2 (LIMP2) is an important component of innate immunity. However, its role in the anti-tumor response remains unknown. Here, we found that the level of LIMP2 mRNA was frequently upregulated in gastric cancer (GC) tissues according to the TCGA, which was confirmed by immunohistochemistry in 329 cases. LIMP2 expression was significantly associated with Lauren classification (P=0.042), depth of invasion (P=0.016), lymph node metastasis (P=0.039) and TNM stage (P=0.027). LIMP2 expression (P < 0.001), differentiation (P < 0.001), TNM stage (P < 0.001) and preoperative CEA (P=0.018) can be used as independent prognostic factors. GC patients with higher levels of LIMP2 mRNA experienced improved clinical outcomes. Mechanically, the TGF-β signaling pathway, the ERBB signaling pathway, and Toll-like receptor signaling were enriched in proteins with higher LIMP2. Moreover, LIMP2 expression was positively related with M1 tumor-associated macrophages (TAMs) in TCGA data, which was verified by capturing LIMP2 and CD86 co-expression in GC samples. The study suggests that LIMP2 expression in GC would predict improved outcomes with M1 TAMs infiltration.