STAT3 and neoplasm: Although the mechanisms of astaxanthin mediating anti-cancer action have not yet been fully clarified, a number of molecular targets of astaxanthin have been proposed, which may explain the anti-tumor effects of this drug, such as NF-κB, STAT3, PI3K/AKT, MAPKs, PPARγ, and so on [31,32,33,34].