VARIABLE REGIONS OF CHROMOSOME-11 LOSS IN DIFFERENT PATHOLOGICAL TISSUES OF A PATIENT WITH THE MULTIPLE ENDOCRINE NEOPLASIA TYPE-I SYNDROME

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant in herited disorder characterized by nodular proliferation of the parathy roid glands and tumors of the anterior pituitary gland, the endocrine pancreas, and the neuroendocrine cell system of the gut. Loss of the p utative tumor suppressor effect of the MEN1 gene is probably responsib le for the development of MEN1-associated tumors. We report here a gen etic study of a female MEN1 patient with the association of nodular hy perplasia of two parathyroid glands, an insulinoma, multiple duodenal gastrinomas, a prolactinoma, and a gastric carcinoid. We performed los s of heterozygosity (LOB) studies of chromosome 11 on all affected tis sues except the insulinoma. Allelic losses of chromosome 11 were detec ted in several tumors, but the chromosomal regions of LOH were differe nt, suggesting that different somatic mutational events are involved i n the pathogenesis of these tumors. LOH of chromosome 11 was also dete cted in the prolactinoma of this patient, which indicates that the MEN 1 gene has a tumor suppressor effect in the pituitary.