Association of dipeptidyl peptidase IV polymorphism with clinicopathological characters of oral cancer

Objective To evaluate the associations between dipeptidyl peptidase IV (DPP4) single‐nucleotide polymorphism (SNP) and clinicopathological characteristics of oral cancer. Methods Four loci of DPP4 SNPs (rs7608798 A/G, rs3788979 C/T, rs2268889 T/C, and rs6741949 G/C) were genotyped by using the TaqMan allelic discrimination in 1238 oral cancers patients and 1197 non‐cancer individuals. Results The percentage of DPP4 SNP rs2268889 TC + CC was significantly higher in the oral cancer participants compared to the control group (odds ratio [OR]: 1.178, 95% confidence interval (CI): 1.004–1.382, p = 0.045). Among 1676 smokers, DPP4 polymorphisms carriers with betel quid chewing were found to have an 8.785‐ to 10.903‐fold risk to have oral cancer compared to DPP4 wild‐type carriers without betel quid chewing. Similar trend was found in individuals with alcohol consumption. Moreover, the oral cancer individuals without cigarette smoking history with at least one varied C allele of DPP4 rs2268889 had a significantly higher percentage of large tumor size with the wild‐type TT homozygote (p = 0.011). Conclusions The DPP4 SNP may correlate to the development of oral cancer in those with cigarette smoking and alcohol consumption. Besides, the DPP4 SNP rs2268889 could relate to worse clinical course of oral cancer in non‐smokers.