Several studies found that the mechanism of HCC drug resistance is complicated, and probably is a combination of two aspects: on one hand, drug delivery to cancer cells is impaired, which generally results from overexpression of ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp); on the other hand, drug sensitivity is affected by various changes in drug resistant cancer cells, including increased repair of DNA damage, reduced apoptosis, and altered metabolism of drug3, 4, 5. The gene discussed is PGP; the disease is cancer.