TGFB1 and cholangiocarcinoma: Magnolol mediates cancer regression through the induction of apoptosis and the suppression of oncogenic pathways, such as transforming growth factor beta (TGF-β)/Samd, insulin-like growth factor 1 receptor (IGF-1R) and nuclear factor-kappaB (NF-κB), in hepatic, pancreatic and prostate cancers as well as cholangiocarcinoma [31,32,33,34].