7-hydroxytryptophan, a novel, specific, cytotoxic agent for carcinoids and other serotonin-producing tumors. Walther, D.J., Peter, J.U. and Bader, M. ORCID: https://orcid.org/0000-0003-4780-4164 Cance 94 (12): 3135-3140. 1 January 2002