Tehran University Medical Journal

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Background: Medullary thyroid cancer (MTC), includes 5-10% of all the thyroid cancers. RET proto-oncogene mutations have been found in association with MTC development. Therefore, identification of the mutations in RET can allow early diagnosis of the families who are at the risk of the disease. The goal of this study was to investigate existence and association between mutations in exon 19 of the RET proto-oncogene in an Iranian population medullary thyroid cancer patients and their family members. Methods: This study was run in the research laboratory of Research Institute for Endocrine Research Center Shahid Beheshti University of Medical Sciences from May, 2013 to May, 2014. In this study, 110 patients with confirmed medullary thyroid carcinoma were selected and examined. At first, the genomic DNA content of the peripheral white blood cells (WBC) of the samples were extracted using a saturated salting out and proteinase K standard method. Exon 19 of the RET proto-oncogene using polymerase chain reaction (PCR) method was amplified. Then the desired PCR products formation was confirmed by electrophoresis technique for true amplification, and finally the amplified samples were used for direct sequenced for finding and assessing any possible mutations Results: In this study, two nucleotide changes at position rs2075912 (Y: T/C) and position rs2075913 (W: T/A) exon 19 RET proto-oncogene were found in the patients with medullary thyroid cancer. The frequency of both nucleotide changes were higher in men than women with medullary thyroid cancer. The frequency of the rs2075912 and rs2075913 were 11.2 and 6.3% higher in men than women. But in statistical analysis, there was no association between age, sex and the founded two mutations. Conclusion: In addition to mutations in other exons of proto-RET, mutations in exon 19 can also be used for early detection and confirmation of medullary thyroid carcinomas.