AQP1 and cancer: We previously showed that the epimers of Rg3 have stereoselectivity in their anti-cancer actions [11], as only SRg3 inhibited the proliferation of MDA-MB-231 (100 μM) and blocked aquaporin 1 (AQP1) water channel (50 μM), which plays important roles in the proliferation, migration, and invasion of cancer cells and in angiogenesis.