Previously, we identified CD39+Vδ T cells as the dominant Tregs in colon cancer.12 Here, we aimed to explore whether there is a specific subtype of Vδ1+ T cells in BC that plays a major immunosuppressive role by evaluating the expression of regulatory immune cell markers (CD27, CD25, CD39, CD73, CTLA-4, CD122 and FoxP3) on Vδ1/2+ T cells isolated from PBHDs and Vδ1/2+ T cells isolated from peripheral blood of breast cancer patients (PBBCs), normal breast tissues (NT) and breast cancer (BC) tissues (Fig. 2a–d, Supplementary Fig. S3). This evidence concerns the gene CTLA4 and malignant colon neoplasm.