BCL2L1 (BCL2 Like 1) is a protein belonging to the Bcl-2 family that plays a crucial role in regulating apoptosis, or programmed cell death. By blocking the release of factors that initiate cell death from the mitochondria, BCL2L1 promotes cell survival and helps maintain cellular health under stress. It is present in many tissues and is involved in disease processes, including cancer, where its overexpression enables cancer cells to evade apoptosis. This resistance is often associated with chemotherapy failure and worse outcomes for cancer patients.