RET isoforms were expressed at different levels in MTC, PHEO, PTC, and normal thyroid tissues: RET9 expression was higher in PHEO than in MTC, PTC, and normal thyroid tissues.
MEN2B is a very rare autosomal dominant hereditary tumor syndrome associated with medullary thyroid carcinoma (MTC) in 100% cases, pheochromocytoma in 50% cases and multiple extra-endocrine features, many of which can be quite disabling.
The remaining 15 RET mutation carriers did not exhibit CLA; of these, 1 presented with MTC and pheochromocytoma, 9 with MTC only, 2 with elevated serum calcitonin, and 3 younger subjects with normal serum calcitonin levels.
Of the 92 cases included 64% had presented as an incidentaloma, 32% as a suspected pheochromocytoma and 4% had been screened because of previously diagnosed MEN2A.
The remaining 15 RET mutation carriers did not exhibit CLA; of these, one presented with MTC and pheochromocytoma, nine with MTC only, two with elevated serum calcitonin and three younger subjects with normal serum calcitonin levels.
Familial screening for rearranged during transfection mutation and lifelong monitoring for associated pheochromocytoma should be emphasized in hereditary medullary thyroid carcinoma.
The findings propose a classification of 15 of the 26 VUS in RET without any well-defined risk profiles and suggest that the G691S SNP, or a combination of SNPs, may be associated with the development of PHEO.
Multiple endocrine neoplasia type 2A (MEN2A) is a condition with inherited autosomal dominant mutations in RET (rearranged during transfection) gene that predisposes the carrier to extremely high risk of medullary thyroid cancer (MTC) and other MEN2A-associated tumors such as parathyroid cancer and/or pheochromocytoma.
Phaeochromocytoma was diagnosed in 85/309 patients with RET mutations in the following exons (phaeos/all carriers, %): exon 11 (56/120, 46.6%); exon 16 (7/17, 41.2%), exon 10 (14/47, 29.8%), and exon 13-15 (2/116, 1.7%).
Germline mutations in codon 918 of exon 16 of the RET gene (M918T) are classically associated with multiple endocrine neoplasia type 2B (MEN 2B) with highly aggressive medullary thyroid cancer (MTC), pheochromocytoma and a unique phenotype.
RET germline mutations cause multiple endocrine neoplasia type 2 syndrome (MEN 2A) characterized by complete penetrance of medullary thyroid cancer (MTC), and lower prevalence of Pheo and hyperparathyroidism.
This study aimed to determine the mutation underlying MEN2A in a female patient diagnosed with bilateral pheochromocytoma at age 31 years and with medullary thyroid carcinoma (MTC) 6 years later.
Rarely, patients present with typical physical features of MEN2B but without associated endocrinopathies (medullary thyroid carcinoma or pheochromocytoma) or a RET gene mutation; this clinical presentation is thought to represent a distinct condition termed 'pure mucosal neuroma syndrome'.