27-BP DELETION IN THE RET PROTOONCOGENE AS A SOMATIC MUTATION ASSOCIATED WITH MEDULLARY-THYROID CARCINOMA

Medullary thyroid carcinoma (MTC) occurs as a sporadic tumor or in con nection with the inherited cancer syndromes of multiple endocrine neop lasia (MEN) types 2A and 2B and familial MTC. Missense RET protooncoge ne mutations of one of cysteine codons in exons 10 and 11 are found in the majority of families with MEN 2A and or familial MTC. In MEN 2B, mutations at codon 918, exon 16, have been identified in most of the a ffected individuals, In a significant amount of sporadic MTC somatic c odon 918 mutations appear. In addition to these, a 6-bp deletion inclu ding codon 630 and a 24-bp deletion including codon 634 combined with a 6-bp insertion have been observed. We report on a 27-bp deletion in exon 10 as a somatic mutation associated with a sporadic medullary thy roid carcinoma.