We stably transfected NCI-N87 cells, a HER2-overexpressing gastric cancer cell line that does not express PDL1 when cultured in vitro (data not shown), with a PDL1 construct to obtain a PDL1/HER2 double-overexpressing cancer cell line (N87-PDL1) that could potentially respond to trastuzumab and anti-PD1 mAbs. Here, CD274 is linked to gastric cancer.