Thus, having observed that increased YAP1/TEAD activity influenced BT-474.r2T cell proliferation, we aimed to assess the effects of the combined treatment of trastuzumab and verteporfin over the proliferation and apoptosis of tumor cells by measuring the expression of pH3 and c-casp3 in mouse BT-474.r2T xenografts. The gene discussed is YAP1; the disease is neoplasm.