title: Somatic mutations in the RET protooncogene in Japanese and Chinese sporadic medullary thyroid carcinomas.
abstract: Despite advances in the understanding of the genotype-phenotype correlation in multiple endocrine neoplasia type 2A and 2B (multiple endocrine neoplasia (MEN) 2A, MEN 2B), and familial medullary thyroid carcinoma (FMTC), the frequency and prognostic relevance of RET protooncogene mutations in sporadic medullary thyroid carcinomas (MTCs) remain controversial. To study somatic mutations in the RET protooncogene in Japanese and Chinese sporadic MTCs and to analyze comparatively the correlation between RET mutation and tumor differentiation, we investigated somatic mutations in the RET protooncogene in 20 Japanese and 20 Chinese sporadic MTCs by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Of the 40 sporadic MTCs, 13 had a point mutation in codon 918 of exon 16, a frequency of 32.5%. There was no significant difference in the frequency between Japanese and Chinese sporadic MTCs, as 30% of the Japanese and 35% of the Chinese sporadic MTCs contained this mutation. We did not observe any correlation between the presence or absence of codon 918 mutation and tumor differentiation in either Japanese or Chinese sporadic MTCs. Our findings indicate that the frequency of RET somatic mutations is similar in Japanese and Chinese sporadic MTCs, and the presence or absence of RET mutation does not correlate with the differentiation of sporadic MTCs.
authors.affiliation: Second Department of Pathology, Wakayama Medical College, China.
authors.forename: L
authors.initials: L
authors.lastname: Shan
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: H
authors.initials: H
authors.lastname: Utsunomiya
authors.forename: N
authors.initials: N
authors.lastname: Shou
authors.forename: X
authors.initials: X
authors.lastname: Jiang
authors.forename: X
authors.initials: X
authors.lastname: Jing
authors.forename: T
authors.initials: T
authors.lastname: Yokoi
authors.forename: K
authors.initials: K
authors.lastname: Kakudo
mesh_terms: D018276:Carcinoma, Medullary / Q000235:genetics*; D002681:China; D029721:Drosophila Proteins; D005787:Gene Frequency; D006801:Humans; D007564:Japan; D009154:Mutation; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics*
chemical_list: D029721:Drosophila Proteins; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila