CTLA4 and neoplasm: This study showed that rFlu‐CTLA4 repressed tumor cell growth and prolonged the OS of treated mice.[161] Moreover, rFlu‐huCTLA4 is another engineered IAV with the same function, which can efficiently replicate in various cells and have selective cytotoxicity in HCC cells than in normal liver cells. Intratumoral injection of rFlu‐huCTLA4 condensed tumor growth in vivo and prolonged the survival of mice.