Absence of somatic RET gene mutation in sporadic parathyroid tumors and hyperplasia secondary to uremia, and absence of somatic MEN1 gene mutation inMEN2A-associated hyperplasia

Germline mutations of the MEN1 gene are found in more than 85% of multiple endocrine neoplasia type 1 (MEN1) patients, and germline mutations of the R ET gene are found in more than 95% of multiple endocrine neoplasia type 2 ( MEN2) patients. Parathyroid hyperplasia is seen in more than 90% of MEN 1 a nd about 15% of MEN2A patients. To date, somatic MEN1 mutations are reporte d in about 20% of sporadic parathyroid tumors. To elucidate the genetic bas is of parathyroid tumor development, we examined somatic RET gene mutations in sporadic parathyroid tumors and hyperplasia secondary to uremia, and so matic MEN1 gene mutations in parathyroid hyperplasia from MEN2A patients. A total of 145 parathyroid tumors comprising 129 sporadic parathyroid tumors , 14 hyperplastic lesions secondary to uremia: and two hyperplastic lesions from MEN2A patients were examined. DNA was extracted from fresh frozen par athyroid tissue. Exons 2-10 of the MEN1 gene and exons 10 and 11 of the RET gene were sequenced. No somatic RET gene mutations were found in the 129 s poradic parathyroid tumors or 14 parathyroid hyperplastic lesions secondary to uremia. No somatic MEN1 gene mutations were found in the two parathyroi d hyperplasia from MEN2A patients. These data suggest that RET gene mutatio n may not be involved in the development of sporadic parathyroid tumors and hyperplasia secondary to uremia and that MEN1 gene mutation may not be or is rarely associated with development of parathyroid hyperplasia in MEN2A p atients. (C) 2000 Editions scientifiques et medicales Elsevier SAS.