In another report, metformin decreases infiltration of FOXP3 T regulatory cells in intratumor regions, increases CD8 T cell infiltration in the peritumoral leading-edge stroma, and increases the CD8/FOXP3 ratio both in tumor and leading-edge stroma of primary head and neck squamous cell carcinoma [15]. This evidence concerns the gene CD8A and head and neck squamous cell carcinoma.