Sampling technique influences the detection of K-ras mutations in normal appearing mucosa of colorectal cancer patients

Int J Oncol. 1999 Aug;15(2):391-8. doi: 10.3892/ijo.15.2.391.


Based on three colorectal cancer cell lines with specified K-ras status, a sensitive PCR-RFLP assay was established detecting one K-ras mutant among 106 wild-type cells. Using this assay for tissues of 124 colorectal cancer patients, 59 tumor (46%) and 11 mucosa samples (9%) were found to harbor a K-ras mutation. When using the same scalpel for collecting tumor and mucosa tissues (group A), 18% of the patients had a matching K-ras mutation in both tissues, but this coincidence was seen in 3% of patients only, when separate scalpels were used (group B). Thus we conclude that the sampling technique used for collecting specimens is a major contributor to the detection of K-ras mutations in normal appearing mucosa when a highly sensitive detection technique is used.

MeSH terms

  • Aged
  • Colorectal Neoplasms / genetics*
  • Female
  • Genes, ras*
  • Humans
  • Intestinal Mucosa*
  • Male
  • Mutation
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length
  • Reference Values
  • Sensitivity and Specificity
  • Sequence Analysis, DNA
  • Specimen Handling / methods*
  • Tumor Cells, Cultured