This led to the assignment of (2′S,5′S)-tetrahydropyrazino[1′,2′:1,6]-di{2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole}-1′,4′-dione (THPDTPI), a previously reported anti-tumor agent [8], as a potential inhibitor of P-selectin. The gene discussed is SELP; the disease is neoplasm.