PTGDR and hepatocellular carcinoma: To investigate whether the lncRNA KIF9-AS1 plays a role in HCC by regulating RAI2 expression, we knocked down only RAI2 expression in Huh-7 cells and set up a functional rescue experiment with sh − KIF9 − AS1 + sh − NC and sh − KIF9 − AS1 + sh − RAI2 groups.