Effects of tobacco smoking on the tumor immune microenvironment in head and neck squamous cell carcinoma

This study was designed to measure immune cell differences between HNSCC patients according to smoking history. We measured CD3, CD8, FoxP3, PD-1 and PD-L1 for immune markers and Pancytokeratin to distinguish between tumor and surrounding tissue. We observed that current smokers have significantly lower numbers of immune cells surrounding the tumor than former or never smokers. GSEA analysis of RNAseq data from this cohort suggests that smoking is associated with reduced Interferon (IFN) Alpha and Gamma levels, and also with reduced levels of IFN-response cytokines CXCL9, 10 and 11. These results emphasize the hypothetical benefits of smoking cessation during treatment for HNSCC.