Breg cells affect immune cells such as T cells and NK cells or cancer-associated fibroblasts (CAFs) by secreting anti-inflammatory IL-10, IL-35, and TGF-β or by expressing cell-membrane bound immune-checkpoint molecules, including PD-1, PD-L1, and granzyme B (GrB) in solid tumors (2, 36). This evidence concerns the gene IL10 and cancer.