YM155 is primarily used in cancer research due to its ability to inhibit survivin, a protein that prevents apoptosis in tumor cells. By suppressing survivin expression, YM155 promotes programmed cell death in various cancer types, including lung, prostate, and breast cancers. It has shown potent anti-tumor activity in preclinical models, especially when combined with other chemotherapeutic agents or radiation therapy. Its role as a first-in-class survivin suppressant makes it a valuable tool in oncology drug development and a candidate for clinical trials targeting resistant or aggressive tumors.