Association of MICA gene Exon-5 polymorphism in oral submucous fibrosis.

Objective: The present study was conducted to explore the allele frequencies of MICA gene Exon-5 transmembrane and to measure the circulatory MICA levels in various histologic grades of patients with oral submucous fibrosis (OSF) compared to healthy individuals.

Study Design: We enrolled a total of 595 patients for this cross-sectional study and divided them into 2 groups: healthy controls (n = 320) and patients with OSF (n = 275). Further, patients with OSF were subdivided based on their histologic gradings. The genomic DNA was extracted followed by a polymerase chain reaction and genotyping using the ABI Prism DNA Sequencer (ThermoFisher Scientific, Inc., Waltham, MA, USA).

Results: Our study showed that the A5 allele of the MICA gene in the Exon-5 region conferred significant risk for patients with OSF. With reference to the histologic gradings of OSF, we found that the MICA gene conferred statistically significant risk among patients with grade III OSF. On the other hand, the A8 allele of MICA gene in the Exon-5 region conferred significant protection among the overall OSF cohort and in the grade III of histologic grade. Finally, the circulatory human MICA levels were found to have a stepwise increase from grade I toward grade III in patients with OSF.

Conclusion: Our results suggested that the A5 allele in MICA might confer risk for the progression of OSF among the South Indian ethnic population.