To validate YAP binding at VSIR and PD-L2, we transduced BT474 and MCF7 epithelial breast cancer cells with lentiviruses expressing Flag-tagged YAP-5SA (an active form of YAP) [63], and performed a ChIP assay with anti-Flag antibodies or an IgG antibody control (PCR primers in Table 2). This evidence concerns the gene PDCD1LG2 and breast cancer.