BIRC5 and central nervous system cancer: Low survivin expression in tumor tissue has been associated with better survival rates in various types of cancers, including bladder, esophageal, pancreatic, lung, colorectal, breast, gastric, ovarian, and gallbladder cancers as well as medulloblastomas and gliomas.[23,24,43,46,49,57–65] By contrast, some studies have shown that patients with high survivin levels exhibit improved survival.