An insertion/deletion polymorphism in the interleukin-1A 3'untranslated region confers risk for gastric cancer

OBJECTIVE: The aim of the study was to evaluate whether the insertion/deletion polymorphism (rs3783553) locating in the 3' untranslated region (3' UTRs) of IL-1A was related to the risk of gastric cancer (GC) in a Chinese population and explore the possible molecular mechanism. METHODS: Genomic DNA was extracted from peripheral venous blood of 519 GC patients and 536 healthy control individuals. The IL-1A rs3783553 polymorphism was genotyped by using a polymerase chain reaction assay. The vectors containing the insertion or deletion allele were constructed, and luciferase assay was used to detect the effect of the polymorphism on the transcriptional activity of IL-1A. RESULTS: Strong evidence of association was observed between the IL-1A rs3783553 polymorphism and susceptibility to GC in the study. In addition, the 'TTCA' insertion allele of rs3783553 disrupts the binding site for miR-122 and miR-378, thereby increasing transcription of IL-1 alpha in vitro. CONCLUSION: These findings suggest that functional polymorphism rs3783553 in IL-1A could contribute to GC susceptibility, possibly or at least partially through affecting the transcriptional activity of IL-1A.