Multimodal genomic markers predict immunotherapy response in the head and neck squamous cell carcinoma
Immune checkpoint blockade (ICB) therapy has had a major impact on the clinical management of head and neck squamous cell carcinoma (HNSCC). However, clinical responses to ICB are observed in only a fraction of patients. In the present paper, we used multimodal approaches to a) evaluate the utility of existing ICB biomarkers including tumor mutation burden (TMB), microsatellite instability (MSI), and a T-cell specific signature in predicting therapy response in HNSCC using TCGA cohort, and; b) identify a novel molecular signature to predict ICB therapy response using an ICB clinical trial of HNSCC. Our results confirm previous reports showing TMB efficacy as a biomarker and its outcome can be influenced by age, tumor sub-site, and smoking status; and that High-TMB and high-MSI tumors are associated with T-cell signature, and better survival probability in the HNSCC. We go on to demonstrate that High-TMB and high-MSI utilizes cell-cycle/cell proliferation processes for their molecular functionality; and identify a novel Cell Proliferation ICB-therapy Predicting (CPIP) signature capable of predicting ICB therapy response in HNSCC, retrospectively, where traditional biomarkers of ICB response were insufficient. In summary, the present study defines strategies and novel signatures that can be appropriately used for patient selection for ICB therapy that can improve the clinical outcomes of HNSCC patients.