CA9 and hepatocellular carcinoma: When patient-derived cells were cultured in the chip for 10 days, the phenotypic gene profiles were maintained with respect to hypoxia (CAIX, VEGFR, GLUT1), drug resistance (ABCB1, ABCC2, GSTP1), ECM remodeling (CD44, Vim, MMP9), and HCC indicators (AFP) in the normoxic and hypoxic zones.