NECTIN4 and neoplasm: For subsequent experiments aimed at evaluating R-421 anticancer efficacy in immunocompetent mouse models, we expressed human nectin4 in murine tumor cells and originated transgenic CT26-hN4, Renca-hN4, and LLC1-hN4, syngeneic with BALB/c and C57BL/6 mice, respectively (Figure 2, Panel 4).