title: Distinctive clinicopathological features of Ki-ras mutated colorectal cancers.
abstract: OBJECTIVE
  We explored the relationship between the mutation pattern of Ki-ras and the clinicopathological features of colorectal cancers (CRCs).
  
  
  METHODS
  Relationships between clinicopathological parameters and Ki-ras mutation status were analyzed in 255 CRC patients using the chi-square and student t-tests. Kaplan-Meier survival curves were compared using the log-rank test.
  
  
  RESULTS
  Ki-ras mutation occurred in 43.9% of tumors, and 83% affected codon 12. The most frequent mutations were GGT->GAT (Gly->Asp) (37.5%), followed by GGT->GTT (Gly->Val) (31.3%), both in codon 12. The frequency of Ki-ras mutation was similar for different tumor stages (38.2-47.8%). The mucin component of tumors was significantly associated with Ki-ras mutation. The 4-year overall and disease-free survival was 61% and 54%, respectively, for patients with Ki-ras mutated tumors, and 73% and 60% for patients with nonmutated tumors (not statistically significant). Patients with Ki-ras mutated tumors had lower plasma folate (24 ng/dl) than those bearing nonmutated tumors (37 ng/dl). Patients with G->T Ki-ras mutations had the lowest folate level (22 ng/dl), followed by those with G->A mutations (25 ng/dl).
  
  
  CONCLUSIONS
  Ki-ras mutated colorectal tumors have a higher mucin production and higher differentiation, and are associated with lower plasma folate levels and a relatively poorer disease outcome.
authors.affiliation: Division of Colon & Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, National Yang-Ming University, Taipei, Taiwan. jklin@vghtpe.gov.tw
authors.forename: Jen-Kou
authors.initials: JK
authors.lastname: Lin
authors.forename: Shih-Ching
authors.initials: SC
authors.lastname: Chang
authors.forename: Huann-Sheng
authors.initials: HS
authors.lastname: Wang
authors.forename: Shung-Haur
authors.initials: SH
authors.lastname: Yang
authors.forename: Jeng-Kai
authors.initials: JK
authors.lastname: Jiang
authors.forename: Wei-Chone
authors.initials: WC
authors.lastname: Chen
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Lin
authors.forename: Anna Fen-Yau
authors.initials: AF
authors.lastname: Li
mesh_terms: D000368:Aged; D002118:Calcium / Q000097:blood; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000097:blood / Q000235:genetics* / Q000473:pathology*; D004252:DNA Mutational Analysis; D005260:Female; D005492:Folic Acid / Q000097:blood; D005787:Gene Frequency / Q000235:genetics; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis
chemical_list: D005492:Folic Acid; D002118:Calcium