They were isolated fromthe marine Aspergillus fumigatus strain BM939 byOsada and co-workers in 1996.32 Despiteits less rigid structure, tryprostatin A (4) was foundto resensitize ABCG2-overexpressing cancer cells whose growth hadbeen inhibited by the anticancer drug (and ABCG2 substrate) mitoxantrone,33 albeit with lower potency than 1. The gene discussed is ABCG2; the disease is cancer.