TOP1 and colorectal carcinoma: For example, camptothecins (103), alkaloids derived from Camptotheca acuminata that could inhibit DNA topoisomerase I (104), are antitumor agents in the treatment of gastrointestinal cancer, which have been proven to prolong the survival period of early-stage CRC patient by stimulating STAT3 signaling and suppressing PKIP phosphorylation (105).