RET Gene Analysis in Patients with Medullary Thyroid Carcinoma.

BACKGROUND: Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor from the para follicular C cells of the thyroid gland. It occurs either sporadically or as part of an inherited syndrome. It is caused by an autosomal dominant mutation in the RET (Rearranged during Transfection) proto-oncogene.

METHODS: The studied population consisted of 47 patients diagnosed with MTC in a specific population of northwest Iran along with their three children. Blood samples were collected from all subjects, genomic DNA was extracted and RET exons 10, 11, 13, 14, 15, and 16 were analyzed using PCR and direct sequencing.

RESULTS: 32 missense mutations were identified in exons 10 (6.25%) and 11 (84.4%). Moreover, two novel mutations in codon 595 in exon 10 (E595D and E595A) and a new mutation in codon 689 exon 11 (S689T) were detected, and a new nucleotide change was found in exon 11 (T675T). Four different polymorphisms were also identified in exons 11, 13, 14, and 15. Based on our data, the frequency profile of RET mutations in the Azari population of Iran with MTC is 61.7%. The most frequent mutation in our population was C364G, whereas in most populations it is C634R.

CONCLUSIONS: These results underline the importance of the genetic background of family members of any patient with MTC.