Genetic variants in microRNA-146a (C>G) and microRNA-1269b (G>C) are associated with the decreased risk of oral premalignant lesions, oral cancer, and pharyngeal cancer.

Abstract Objective To investigate the relationships between two single-nucleotide polymorphisms at miR-146a C > G (rs2910164) and miR-1269b G > C (rs7210937) and the risk of developing oral premalignant lesions (OPLs), oral squamous cell carcinoma (OSCC), pharyngeal SCC (PSCC), and oral and pharyngeal SCC (OPSCC). Design Genotyping of miR-146a C > G and miR-1269b G > C was performed in two case-control studies using the TaqMan assay. A total of 197 healthy control subjects, 241 OPLs patients, and 188 OPSCC patients who habitually chewed betel quid (BQ) were recruited into one case-control study. Additionally, 668 cancer-free control subjects and 658 OPSCC patients were recruited into the other case-control study. Results The G/G genotype at miR-146a C > G was associated with the decreased risk of OSCC [adjusted odds ratio (AOR) = 0.66, P = 0.040], PSCC (AOR = 0.42, P = 0.013), and OPSCC (AOR = 0.63, P = 0.020). Additionally, the C allelic type and C/C genotype at miR-1269b G > C decreased the risk of BQ-related oral leukoplakia (C vs. G: AOR = 0.68, P = 0.012; C/C vs. G/G: AOR = 0.43, P = 0.009), BQ-related OPLs (C vs. G: AOR = 0.69, P = 0.008; C/C vs. G/G: AOR = 0.44, P = 0.005), and BQ-related OPSCC (C vs. G: AOR = 0.65, P = 0.003; C/C vs. G/G: AOR = 0.47, P = 0.011). In OPSCC patients, the G/G genotype of miR-146a was correlated with well-differentiated cells (P = 0.041), and the G/C and C/C genotypes of miR-1269b were correlated with the absence of lymph node involvement (P = 0.031), especially in OSCC patients (P = 0.038 and P = 0.007, respectively). Conclusion The genetic variants of miR-146a and miR-1269b are biomarkers against the development of OPLs and OPSCC.