BIRC5 and breast cancer: Additionally, mitochondrial survivin can block apoptosis independently of the cell cycle.[6,7] Increased survivin expression is associated with poor prognosis in various cancers, including hematological malignancies; lung, colon, bladder, ovarian, prostate, hepatocellular, pancreatic, and esophageal cancers; and neuroblastoma.[8–17] However, its role as a prognostic factor for breast cancer remains controversial.