Analysis of RAS mutation in thyroid nodular hyperplasia and follicular neoplasm in a Korean population

To investigate the difference in frequency of RAS mutations between nodular hyperplasia (NH), follicular thyroid adenomas (FTAs) and follicular thyroid carcinomas (FTCs) in a Korean population.

RAS mutations in 50 NH, 57 FTAs and 39 FTCs between January 2002 and May 2015 were analysed by pyrosequencing.

Nine nodules of 50 NHs (18%), 18 nodules of 39 FTCs (46.2%) and 19 nodules of 57 FTAs (33.3%) harboured RAS mutations. Three FTCs and three FTAs showed two point mutations simultaneously. N-RAS codon 61 (n = 6 of 9, 66.7%) and H-RAS codon 61 (n = 3 of 9, 33.3%) were found in NHs. K-RAS codons 12-13, K-RAS codon 61, N-RAS codons 12-13 and H-RAS codons 12-13 were not found in NHs. N-RAS codon 61 (n = 7 of 21, 33.3%), K-RAS codons 12-13 (n = 6 of 21, 28.6%), H-RAS codon 61 (n = 4 of 21, 19.0%), K-RAS codon 61 (n = 3 of 21, 14.3%) and N-RAS codons 12-13 (n = 1 of 21, 4.7%) were found in FTCs, and N-RAS codon 61 (n = 10 of 22, 45.5%), K-RAS codons 12-13 (n = 5 of 22, 22.7%), H-RAS codon 61 (n = 5 of 22, 22.7%), K-RAS codon 61 (n = 1 of 22, 4.5%) and N-RAS codons 12-13 (n = 1 of 22, 4.5%) were observed in FTAs.

The frequencies of RAS mutations among our Korean population were 18% in NHs, 46.2% in FTC and 33.3% in FTAs. N-RAS codon 61 was the most frequent mutation in NHs, FTCs and FTAs, and the frequency was not significantly different among the three groups. K-RAS codons 12-13 were the second most commonly involved site in FTCs and FTAs, whereas no mutation was detected at this site in NHs.