Malignant carcinoid tumours.
D002276:Carcinoid Tumor / Q000378:metabolism*; D004067:Digestive System Neoplasms; D041981:Gastrointestinal Tract; D006801:Humans; D009369:Neoplasms; D012701:Serotonin / Q000378:metabolism*
D012701:Serotonin
ARGENTAFFINOMA/metabolism; GASTROINTESTINAL SYSTEM/neoplasms; SEROTONIN/metabolism