title: Analysis of K-ras codon 12 and TP53 mutations in patients with advanced colorectal carcinoma.
abstract: BACKGROUND
  Colorectal cancer (CRC) is one of the most common types of cancer, affecting 3 - 5% of the global population. K-ras protooncogene and TP53 tumour suppressor gene mutations are among the most common genetic alterations detected in advanced colorectal tumours.
  
  
  OBJECTIVE
  To investigate the role of K-ras codon 12 and TP53 exons 5 - 9 mutations in late-stage CRC patients.
  
  
  METHODS
  Blood samples were collected from 249 CRC patients, of whom 147 presented with advanced carcinoma. K-ras codon 12 mutations were analysed using polymerase chain reaction-restriction fragment length polymorphism, while direct sequencing was used in screening for TP53 exons 5 - 9 mutations.
  
  
  RESULTS
  No significant changes were observed in TP53 exons 5 - 9, except for two cases in which nucleotide replacements were observed in the non-coding regions in intron 4 (c.376-19C&gt;T) and intron 9 (c.993+12T&gt;C). Heterozygous mutations in K-ras codon 12 were observed in 79 individuals suffering from advanced CRC (53.7%). Colon and rectal tumours were equally distributed among the heterozygotes, but colon tumours were mostly present in wild-type homozygotes (84.6%). There was also a predominance of Caucasians among heterozygotes and a predominance of Asians among the wild-type homozygotes.
  
  
  CONCLUSIONS
  Analysis of peripheral blood samples of CRC patients suffering from advanced carcinoma has prognostic value only for K-ras codon 12 mutations, and not for TP53 mutations.
authors.affiliation: International Centre for Genetic Engineering and Biotechnology and University of Cape Town. iqbal.parker@icgeb.org.
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Parker
authors.forename: G
authors.initials: G
authors.lastname: Zhunussova
authors.forename: L
authors.initials: L
authors.lastname: Djansugurova
authors.forename: E
authors.initials: E
authors.lastname: Khussainova
authors.forename: B
authors.initials: B
authors.lastname: Zhunusbekova
authors.forename: G
authors.initials: G
authors.lastname: Afonin
authors.forename: D
authors.initials: D
authors.lastname: Khaidarova
authors.forename: M
authors.initials: M
authors.lastname: Matejcic