Papillary Thyroid Carcinoma and Body Mass Index: The Role of Immune System in Tumor Microenvironment

Papillary thyroid cancer (PTC) is linked to obesity, but the biological mechanisms that may explain this connection have been only partially described. Potential factors that combine overweight/obesity with this cancer should be searched for in the immune pathways and chronic inflammation onset. In this study, we evaluated the role of the immune system in patients affected by PTC and stratified them according to Body Mass Index (BMI). An analysis of the expression profiles of >700 immune-related genes was performed in 36 PTCs, subdivided into four categories: underweight (A), normal weight (B), overweight (C), and subjects living with obesity (D). B was considered a reference category. In our study, the immune microenvironment of PTCs did not seem strongly influenced by BMI. However, based on the interaction from in silico protein-protein analysis, we found that the dysregulation profiles of groups A or D were similar as concerns pathways involved in T-cell differentiation, macrophage activation, regulation of the cell cycle, and senescence processes. Furthermore, we found significant downregulation of HMGB1 in the A and D categories, with upregulation of ARG2 in the D category. Although further studies are necessary, these genes may provide an opportunity to better understand immunometabolism in thyroid cancer.