Difference in tumor mutation burden between squamous cell carcinoma in the oral cavity and larynx.

Objectives: This study aimed to evaluate the difference in tumor mutation burden (TMB) between oral cavity squamous cell carcinoma (OCSCC) and larynx squamous cell carcinoma (LSCC).

Materials And Methods: Patients with OCSCC or LSCC were identified from datasets within The Cancer Genome Atlas. Somatic mutations and clinical information were included in the analysis. A Poisson regression model was used to evaluate the association of TMB with the primary cancer sites.

Results: We identified 5 datasets that included 396 OCSCC patients and 143 LSCC patients. Patients with LSCC had a significantly higher TMB than patients with OCSCC (crude risk ratio: 0.60, 95% confidence interval: 0.51-0.70, P < 0.001; adjusted risk ratio: 0.57, 95% confidence interval: 0.49-0.66, P < 0.001).Subgroup analyses suggested that this difference was independent of dataset, age, sex, race, alcohol drinking, smoking status, pathological risk, tumor grade, and tumor stage. Sensitivity analyses confirmed the robustness of this finding.

Conclusion: To the best of our knowledge, this is the first study to identify a significant difference in TMB between OCSCC and LSCC. Though preliminary, these findings might have implications for guiding the development of trials for examining the response of head and neck carcinomas to immune checkpoint inhibitor treatments.