Inactivating mutations in genes that encode either the core cohesin subunits or the regulatory proteins that affect cohesin function (e.g., PDS5A/B, WAPL, CDCA5, NIPBL, MAU2, etc.)are common in numerous cancer types, including bladder, melanoma, colorectal, lung, Ewing sarcoma, and myeloid malignancies. This evidence concerns the gene WAPL and Ewing sarcoma.