Genetic heterogeneity in lung and colorectal carcinoma as revealed by microsatellite analysis in plasma or tumor tissue DNA

Cancer. 2003 May 1;97(9):2308-17. doi: 10.1002/cncr.11324.


Background: Determination of tumor clonality has implications for molecular characterization and the optimal treatment of cancer. Allelotyping allows detection of the two alleles, maternal and paternal, and provides additional information regarding clonal genetic defects. The presence of allelic imbalances (AI) in tumors is a general event, but is not necessary at the same allele (alternative AI). The authors' goal was to determine whether the presence of alternative AI (AA) was a marker of heterogeneity and prognosis.

Methods: To further analyze the heterogeneity of lung tumors, tumor DNA released in the plasma was compared with primary tumor DNA from 24 lung carcinoma patients. The comparison was performed by allelotyping using 12 microsatellites targeting 9 chromosomal regions, taking in each case leukocyte DNA as reference. To extend and confirm these observations, 26 primary colorectal carcinomas with paired synchronous liver metastasis were analyzed using an enlarged panel of 33 microsatellites.

Results: AA were observed in 40% (20 of 50) of all patients, in 25% (6 of 24) of lung carcinoma patients but at a higher level, and in 54% (14 of 26) of colorectal carcinoma patients. They affected different chromosome localizations and each tumor stage. In both types of cancer, patients with AA had a higher AI mean frequency in their primary tumor.

Conclusions: Detection of AA is an original marker of heterogeneous tumors, demonstrating that independent events occurred on specific genetic sites required for cancer progression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / blood
  • Adenocarcinoma / genetics*
  • Adenocarcinoma / pathology
  • Adult
  • Aged
  • Allelic Imbalance
  • Carcinoma, Small Cell / blood
  • Carcinoma, Small Cell / genetics*
  • Carcinoma, Small Cell / pathology
  • Carcinoma, Squamous Cell / blood
  • Carcinoma, Squamous Cell / genetics*
  • Carcinoma, Squamous Cell / pathology
  • Colorectal Neoplasms / blood
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / pathology
  • DNA, Neoplasm / blood
  • DNA, Neoplasm / genetics*
  • Disease Progression
  • Female
  • Gene Frequency
  • Genetic Heterogeneity*
  • Humans
  • Lung Neoplasms / blood
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / pathology
  • Male
  • Microsatellite Repeats / genetics
  • Middle Aged
  • Polymerase Chain Reaction
  • Prognosis


  • DNA, Neoplasm