MK-0752 is a potent, reversible inhibitor of γ-secretase, which inhibits γ-secretase to cleave substrates such as amyloid precursor protein. MK-0752 shows promising effects on inhibiting the growth of several types of cancer cells and was investigated in clinical trials for cancer treatment. For example in ovarian cancer models MK-0752 alone actively induced cell growth inhibition, G2/M phase cell cycle arrest and apoptosis with down-regulation of Notch1 and its downstream effectors in a dose- and time-dependent manner. Moreover, the sequential combination of cisplatin prior to MK-0752 significantly promoted cell apoptosis and inhibited the subcutaneous xenograft growth of ovarian cancer in nude mice. Through its effects on the Notch pathway, MK-0752 reduces the number of breast cancer stem cells in tumorgrafts, enhancing the efficacy of the chemotherapy drug docetaxel in mice with breast cancer tumors. Unfortunately, in phase II clinical trials MK-0752 failed to demonstrate efficacy.