Reduced Oral Squamous Cell Carcinoma Risk Associated with MLH1 rs63749795 Polymorphism in the Dominant Genetic Model

Oral squamous cell carcinoma (OSCC) represents the predominant form of cancer affecting the oral cavity, accounting for more than 90% of all oral malignancies. Despite advancements in treatment, the five-year survival rate has remains relatively unchanged, primarily due to late-stage diagnosis. This study aimed to evaluate the genetic variation in MutL homolog 1 (MLH1) (rs63749795) in patients with OSCC.

A cross-sectional case-control study was performed, including a total of 102 patients diagnosed with OSCC and 100 healthy individuals serving as controls. Genotyping of the MLH1 rs63749795 polymorphism was performed using tetra-primer amplification refractory mutation system-polymerase chain reaction (TP-ARMS-PCR) method, followed by agarose gel electrophoresis.

The predominant genotype observed in both OSCC patients and healthy controls was the CT genotype, with respective frequencies of 45.1% and 55%. The least frequent genotype in both groups was TT, with frequencies of 12.7% in patients and 17% in controls. Most patients were in tumor grade 1 (70.96%) and tumor stage III (35.8%). Among the patients, 53.3% showed lymph node involvement. No statistically significant associations were observed between clinicopathological features and genotypes (P>0.05). The allele frequencies of MLH1 rs63749795 did not differ significantly between patients and controls. However, the rs63749795 polymorphism was associated with reduced OSCC susceptibility under the dominant genetic model (OR = 0.53, 95% CI = 0.29-0.96, P = 0.03 for CT+TT vs. CC genotype).

The MLH1 rs63749795 polymorphism may be associated with reduced susceptibility to OSCC under the dominant genetic model; however, although further studies involving larger populations are needed.