title: Clinico-pathological study of K-ras mutations in colorectal tumors in Saudi Arabia.
abstract: OBJECTIVE
  K-ras gene mutations contribute to the pathogenesis of colorectal cancer. We characterized K-ras mutations in colorectal tumors in patients in the Kingdom of Saudi Arabia, in terms of geographic area, age, gender, histology, stage, and anatomical localization.
  
  
  METHODS
  Medical records and paraffin-embedded tumor samples from 150 consecutive patients with histologically proven colorectal adenocarcinoma referred to two centers in Saudi Arabia were analyzed using an LCD-array kit.
  
  
  RESULTS
  K-ras mutations occurred in 56% of the patients; 48.7% of the mutations were in codon 12, most commonly p.G12V and p.G12D (each 35.6% of codon 12 mutations). Codon 13 mutations occurred in 7.3% of tumors: of these, most were p.G13D (90.9%) with the remainder p.G13R (9.1%). Codon 12 mutations overall were associated significantly with stage IVb tumors (P = 0.022) and rectal tumors (P = 0.028), with a trend of an association with a sigmoid location (P = 0.054). The p.G12V mutation was significantly associated with sigmoid tumors (P = 0.021) and negatively associated with left-sided tumors (P = 0.011), with a trend of an association with age ≥70 years (P = 0.062) and rectal tumors (P = 0.063). Other clinicopathological features were not significantly associated with K-ras mutations.
  
  
  CONCLUSIONS
  K-ras mutations are common among the Saudi colorectal cancer population, especially pG12V and pG12D in codon 12, and are more frequent in sigmoid and rectal adenocarcinomas and stage IVB tumors.
authors.forename: Ali
authors.initials: A
authors.lastname: Zahrani
authors.forename: Magdy
authors.initials: M
authors.lastname: Kandil
authors.forename: Talha
authors.initials: T
authors.lastname: Badar
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Abdelsalam
authors.forename: Abdulla
authors.initials: A
authors.lastname: Al-Faiar
authors.forename: Abdelsalam
authors.initials: A
authors.lastname: Ismail
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001224:Aspartic Acid; D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D011905:Genes, ras; D005998:Glycine; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012189:Retrospective Studies; D012529:Saudi Arabia; D014633:Valine; D018631:ras Proteins / Q000235:genetics*
chemical_list: D003062:Codon; D004273:DNA, Neoplasm; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D001224:Aspartic Acid; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D014633:Valine; D005998:Glycine