Association Between Oral Cavity Cancer and Lymphoma: A Bidirectional Mendelian Randomization Analysis.

PURPOSE: Emerging evidence suggests a potential association between oral cavity cancer (OCC) and lymphoma. This study aimed to investigate whether this association reflects a causal relationship. MATERIALS AND METHODS: A two-sample bidirectional Mendelian randomization (MR) approach was utilized to screen genetic instrumental variables (IVs) obtained from genome-wide association studies (GWAS) of OCC and lymphoma, applied various MR methods (inverse variance weighted [IVW] as the main method) to assess the causal relationship between the two malignancies, and performed sensitivity, heterogeneity, and pleiotropic tests to evaluate reliability. RESULTS: No bidirectional causal association between OCC and Hodgkin lymphoma (HL) or overall non-Hodgkin lymphoma (NHL) was found. Subgroup analysis also showed that no noteworthy bidirectional causal relationship between OCC and NHL subtypes. However, we identified a statistically significant inverse correlation between mature T/NK-cell lymphoma and OCC (IVW: odds ratio [OR] 0.985, 95% confidence interval [CI]: 0.820-0.978, p=0.013). Patients initially diagnosed with mature T/NK-cell lymphoma would have a decreased risk of OCC. CONCLUSION: This MR study ruled out the causal relationship between OCC and lymphoma. Future multiethnic studies with substantial sample sizes are need to replicate our findings.