LCL161 is primarily used in cancer research as a potent antagonist of inhibitor of apoptosis proteins (IAPs), particularly targeting cIAP1, cIAP2, and XIAP. By inhibiting these proteins, LCL161 promotes apoptosis in tumor cells, making it a candidate for investigation in various oncology applications. It has been studied in clinical trials for its ability to sensitize cancer cells to other therapies, including chemotherapy and radiation, especially in solid tumors and hematological malignancies. Its mechanism enhances TNFα-mediated cell death, which can be leveraged in combination treatments to improve therapeutic response. Research continues to explore optimal dosing, patient selection, and synergistic regimens in cancers such as melanoma, breast cancer, and leukemia.