family: potential prognostic biomarkers and therapeutic targets for gastric cancer.

Background: The type IV collagen alpha chain (COL4A) family is a major component of the basement membrane (BM) that has recently been found to be involved in tumor angiogenesis and progression. However, the expression levels and the exact roles of distinct COL4A family members in gastric cancer (GC) have not been completely understood.

Methods: Here, the expression levels of in GC and normal gastric tissues were calculated by using TCGA datasets and the predicted prognostic values by the GEPIA tool. Furthermore, the cBioPortal and Metascape tools were integrated to analyze the genetic alterations, correlations and potential functions of , and their frequently altered neighboring genes in GC.

Results: Notably, the expression levels of in GC were higher to those in normal gastric tissues, while the expression levels of were lower in GC than normal. Survival analysis revealed that lower expression levels of led to higher overall survival (OS) rate. Multivariate analysis using the Cox proportional-hazards model indicated that age, gender, pathological grade, metastasis and expression, are independent prognostic factors for OS. However, TNM stage, lymph node metastasis, Lauren's classification, and were associated with poor OS but not independent prognostic factors. Function-enriched analysis of and their frequently altered neighboring genes was involved in tumor proliferation and metastasis in GC.

Conclusions: These results implied that were potential therapeutic targets for GC. might have an impact on gastric carcinogenesis and subsequent progression, whereas was an independent prognostic marker for GC.