Molecular alterations associated with parathyroid tumors include genomic aberrations in cell division cycle 7 (CDC7) [3–5], cyclin D1 (CCND1) [6–10], cyclin-dependent kinase inhibitor (CDKI) [11], and multiple endocrine neoplasia type 1 (MEN1) [12–17]. The gene discussed is MEN1; the disease is tumor of parathyroid gland.