miRNA genetic variants: As potential diagnostic biomarkers for oral cancer

MicroRNAs (miRNAs) comprise a novel class of small, non-coding endogenous RNAs that have a role in the plethora of regulatory activities by directing their target mRNAs for degradation or translational repression. Single nucleotide polymorphisms (SNPs) in miRNA genes can lead to alteration in mRNA expression, resulting in serious consequences. Detection of miRNA-polymorphisms can potentially improve diagnosis, treatment, prognosis in patients and has extreme implications in the fields of pharmacogenomics and personalization of medicine. The aim of this study is to investigate the association between miR-499 A/G and miR-149 C/T polymorphisms with susceptibility to development of Oral Squamous Cell Carcinoma (OSCC). 200 histopathologically diagnosed and confirmed samples from OSCC patients and 200 control samples from the general population were recruited for the study. All OSCC patients were graded based on their differentiation, and genetic analysis was performed by PCR-RFLP and sequencing. qRT-PCR was carried out to compare the expression of miR-499 and miR-149 in different grades of various stages of OSCC patients concerning to the controls. Further Immunohistochemistry (IHC) was performed to study the target gene of miR-499. The study shows a probable association of miR-499 A/G and miR-149 C/T with susceptibility of OSCC. Random sequencing analysis and Immunohistochemistry contribute to the result that miR-499 A/G increases the susceptibility of OSCC by targeting SOX-6. PCR- Restriction Fragment Length Polymorphism (RFLP) and multivariable logistic analysis revealed that there is a significant association between miR-149 CT + TT and CT and susceptibility of OSCC. Our study suggests that miR-499 A/G and miR-149 C/T polymorphisms may play crucial roles in susceptibility and development of OSCC in Indian population.