qPCR revealed that CDKN2B was highly expressed in PD patients, while RB1, PCNA, and MCM7 exhibited low expression (Fig. 6C), which was consistent with the expression levels in HepG2 resistant cells, indicating that the development of drug resistance in clinical liver cancer patients is closely related with RB1 Signaling pathway (Fig. 6D). This evidence concerns the gene RB1 and liver cancer.