1. Occurrence of two or more primary MEN1-associated endocrine tumors (i.e., parathyroid adenoma, enteropancreatic tumor, and pituitary adenoma) 2. Occurrence of one of the MEN1-associated tumors in a first-degree relative of a patient with a clinical diagnosis of MEN 3. Identification of a germline MEN1 mutation in an individual who may be asymptomatic and has not yet developed serum biochemical or radiological abnormities indicative of tumor development. Here, MEN1 is linked to neoplasm.