The NLRP3 inflammasome activates IL1β, which stimulates tryptophan hydroxylase 1 (TPH1, gene coding the 5-HT biosynthesis rate-limiting enzyme) transcription to increase 5-HT production in colorectal cancer cells, forming a positive feedback loop between 5-HT and NLRP3 signaling. Here, IL1B is linked to colorectal cancer.