Tumors from patients with MEN1 have been observed to harbor the germ-line mutation together with a somatic LOH involving chromosome 11q13 (Friedman et al., 1989; Larsson et al., 1988; Thakker et al., 1989, 1993), or point mutations, as expected from Knudson’s model (Pannett and Thakker, 2001) and the proposed role of the MEN1 gene as a tumor suppressor. Here, MEN1 is linked to neoplasm.