CDKN1B and breast cancer: Patients with MEN4 express MEN1-like milder phenotypes due to CDKN1B germline variants and, less frequently, other non-endocrine neoplasms such as breast cancer, prostate cancer, colon cancer, papillary thyroid carcinoma, angiomyolipoma, and meningioma, although only approximately 100 cases have been reported to date (10, 11).