In vitro Anticancer Activities of Some Triterpene Glycosides from Holothurians of Cucumariidae, Stichopodidae, Psolidae, Holothuriidae and Synaptidae families.  Triterpene glycosides isolated from holothurians are natural products known to possess cytotoxic properties against cancer cells. However, their anticancer prophylactic activity has not been studied sufficiently. The anticancer prophylactic; cytotoxic, and pro-apoptotic properties of 18 triterpene glycosides, as well as their effects on the transcriptional activities of activator protein-I (AP-1) and nuclear factor-KB (NF-KB), were examined using methods that included EGF-induced JB6 C141 P'' cell transformation in soft agar, flow cytometry, MTS assessment of cell viability, and a luciferase activity assay. The compounds inhibited EGF-induced neoplastic JB6 C141 P'' cell transformation in soft agar and caused apoptosis and necrosis of human HL-60 and THP-I leukemia cells. AP- and NF-KB were involved in the cellular response to the treatment by the compounds. Conclusion: glycosides isolated from holothurians of Cucumariidae, Stichopodidae, Psolidae, Holothuriidae and Synaptidae families have potential for development as new antitumor agents and as instruments to study AP-I and NF-kB.