RB1 and hepatocellular carcinoma: Based on the results for the binding efficiency, the Ki values, the molecular interactions of Z-guggulsterone and its comparison with regorafenib, the following proteins were selected for MD simulation: cyclin E1, ezrin, RB1, aminoacylase, transgelin, S100A14, prohibitin and AXIN1, among the HCC proteins; and PDI, CRT and P58, among the ER stress proteins.