title: Differences in K-ras and mitochondrial DNA mutations and microsatellite instability between colorectal cancers of Vietnamese and Japanese patients.
abstract: BACKGROUND
  The incidence of early-onset (under 50 years of age) colorectal cancer (CRC) in the Vietnamese has been reported to be quite higher than that in the Japanese. To clarify the differences in genetic alterations between Vietnamese and Japanese CRCs, we investigated mutations in K-ras and mitochondrial DNA (mtDNA) and high-frequency microsatellite instability (MSI-H) in the CRCs of Vietnamese and Japanese patients.
  
  
  METHODS
  We enrolled 60 Vietnamese and 233 Japanese patients with invasive CRCs. DNA was extracted from formalin-fixed, paraffin-embedded tissue sections. K-ras mutations were examined with PCR-single-strand conformation polymorphism analysis. mtDNA mutations and MSI-H were examined with microsatellite analysis using D310 and BAT-26, respectively.
  
  
  RESULTS
  K-ras mutations were examined in 60 Vietnamese and 45 Japanese CRCs. The frequency of the mutations in the Vietnamese CRCs was significantly higher than that in the Japanese CRCs (8 of 24 [33%] vs 5 of 45 [11%], p =0.048). MSI-H was examined in 60 Vietnamese and 130 Japanese CRCs. The frequency of MSI-H in the Vietnamese CRCs was also significantly higher than that in the Japanese CRCs (6 of 27 [22%] vs 10 of 130 [8%], p =0.030). mtDNA mutations were examined in 60 Vietnamese and 138 Japanese CRCs. The frequency of mtDNA mutations in the Vietnamese CRCs was significantly higher than that in the Japanese CRCs (19 of 44 [43%] vs 11 of 133 [9%], p <0.001). There were no significant differences in clinicopathologic characteristics, such as age, sex, tumour location, and depth, in terms of tumours with/without each genetic alteration in the CRCs of the Vietnamese and Japanese patients.
  
  
  CONCLUSIONS
  These results indicate that the developmental pathways of CRCs in the Vietnamese may differ from those of CRCs in the Japanese.
authors.affiliation: Department of Gastroenterology and Metabolism, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. tmiwata@hiroshima-u.ac.jp.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Miwata
authors.affiliation: Health Service Center, Hiroshima University, Higashihiroshima, Japan. tohiyama@hiroshima-u.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Hiyama
authors.affiliation: Department of Endoscopy, University Medical Center, Ho Chi Minh, Vietnam. quachtrongduc2002@yahoo.com.
authors.forename: Duc Trong
authors.initials: DT
authors.lastname: Quach
authors.affiliation: Department of Pathology, University Medical Center, Ho Chi Minh, Vietnam. huy2903@yahoo.com.
authors.forename: Huy Minh
authors.initials: HM
authors.lastname: Le
authors.affiliation: Department of Pathology, University Medical Center, Ho Chi Minh, Vietnam. hthngocha@yahoo.com.
authors.forename: Ha Ngoc Thi
authors.initials: HN
authors.lastname: Hua
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, Hiroshima, Japan. oka4683@hiroshima-u.ac.jp.
authors.forename: Shiro
authors.initials: S
authors.lastname: Oka
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, Hiroshima, Japan. colon@hiroshima-u.ac.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Pathology, Hiroshima University Hospital, Hiroshima, Japan. arihiro@hiroshima-u.ac.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Arihiro
authors.affiliation: Department of Gastroenterology and Metabolism, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. chayama@hiroshima-u.ac.jp.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D007564:Japan; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D009154:Mutation; D014744:Vietnam
chemical_list: D004272:DNA, Mitochondrial