Breast-Cancer Predisposition in Multiple Endocrine Neoplasia Type 1

Abstract

Women with multiple endocrine neoplasia type 1 related to mutations in the gene encoding menin (MEN1) have approximately twice the risk of breast cancer as do women in the general population. TO THE EDITOR: Multiple endocrine neoplasia type 1 (MEN1) is caused by germline mutations in the MEN1 tumor-suppressor gene and is typically characterized by parathyroid adenomas, duodenopancreatic neuroendocrine tumors, and pituitary adenomas.1 Recent studies in animals2 suggest that MEN1 is involved in breast-cancer initiation. Through its encoding of menin, a coregulator of estrogen receptor α, MEN1 has been implicated in breast-cancer progression.3,4 To clarify the role of MEN1 in human breast cancer, the International Breast Cancer in MEN1 Study Group assessed the incidence of breast cancer in the Dutch longitudinal MEN1 database, which includes more than 90% of Dutch . . .