title: Absence of tyrosine kinase mutations in Japanese colorectal cancer patients.
abstract: Tyrosine kinases, which are important regulators of intracellular signal-transduction pathways, have mutated forms that are often associated with oncogenesis and are attractive targets for therapeutic intervention. Recently, systematic mutational analyses of tyrosine kinases revealed that a minimum of 30% of colorectal cancer contain at least one mutation in the tyrosine kinases. To further explore these mutations, we examined all reported mutations of NTRK3, FES, KDR, EPHA3, NTRK2, JAK1, PDGFRA, EPHA7, EPHA8, ERBB4, FGFR1, MLK4 and GUCY2F genes in the 24 colorectal cancer cell lines. Unexpectedly, among 24 colorectal cancer cell lines, only two cell lines (LoVo and CaR1) harbored mutation C1408T (R470C) in MLK4 gene. The mutation rate was extremely low compared to that previously reported. Therefore, we analyzed mutations in 46 colorectal cancer samples resected from the same number of Japanese patients. Surprisingly, none of the 46 samples contained any of the mutations reported. Based on our study, we advise that a more comprehensive tyrosine kinase gene mutation assay is necessary in the future.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: R-X
authors.initials: RX
authors.lastname: Shao
authors.forename: N
authors.initials: N
authors.lastname: Kato
authors.forename: L-J
authors.initials: LJ
authors.lastname: Lin
authors.forename: R
authors.initials: R
authors.lastname: Muroyama
authors.forename: M
authors.initials: M
authors.lastname: Moriyama
authors.forename: T
authors.initials: T
authors.lastname: Ikenoue
authors.forename: H
authors.initials: H
authors.lastname: Watabe
authors.forename: M
authors.initials: M
authors.lastname: Otsuka
authors.forename: B
authors.initials: B
authors.lastname: Guleng
authors.forename: M
authors.initials: M
authors.lastname: Ohta
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: S
authors.initials: S
authors.lastname: Kondo
authors.forename: N
authors.initials: N
authors.lastname: Dharel
authors.forename: J-H
authors.initials: JH
authors.lastname: Chang
authors.forename: H
authors.initials: H
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Kawabe
authors.forename: M
authors.initials: M
authors.lastname: Omata
mesh_terms: D000368:Aged; D044466:Asian People / Q000235:genetics; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011505:Protein-Tyrosine Kinases / Q000235:genetics*
chemical_list: D011505:Protein-Tyrosine Kinases