Evaluation of tumor microsatellite instability using five quasimonomorphic mononucleotide repeats and pentaplex PCR

Gastroenterology. 2002 Dec;123(6):1804-11. doi: 10.1053/gast.2002.37070.

Abstract

Background & aims: The microsatellite instability (MSI) phenotype is a characteristic of the hereditary nonpolyposis colorectal cancer syndrome as well as approximately 15% of sporadic colon and gastric tumors. It is a valuable diagnostic marker for the identification of hereditary nonpolyposis colorectal cancer cases and may be a molecular predictive marker for the identification of colon cancer patients who benefit from chemotherapy. To evaluate MSI, a reference panel was proposed at an international consensus meeting, comprised of 2 mononucleotide (BAT-25, BAT-26) and 3 dinucleotide repeats. Analysis of BAT-26 is sufficient for detecting the MSI phenotype in most, but not all, cases. Additional results with dinucleotide markers can sometimes lead to incorrect classification of MSI tumors.

Methods: We describe here a single fluorescent multiplex system comprising 5 quasimonomorphic mononucleotide repeats for the detection of MSI tumors.

Results: None of 184 germline DNA samples, including 56 from African subjects, was found to contain allelic size variations in more than 2 of these markers. In contrast, all MSI tumors showed allelic size variations in 3 or more of the microsatellites. Using this assay, we confirmed (or reclassified in 6 cases) the MSI status of 124 colon and 50 gastric primary tumors and 16 colon cell lines.

Conclusions: We propose that using a pentaplex polymerase chain reaction system allows accurate evaluation of tumor MSI status of DNA with 100% sensitivity and specificity without the need to match normal DNA. This assay is simpler to use than those involving dinucleotides and is more specific than using BAT-26 alone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa / ethnology
  • African Continental Ancestry Group / genetics
  • Cell Line
  • DNA, Neoplasm / genetics*
  • Endometrial Neoplasms / genetics*
  • European Continental Ancestry Group / genetics
  • Female
  • Fluorescence
  • Gastrointestinal Neoplasms / genetics*
  • Humans
  • Microsatellite Repeats*
  • Paris / ethnology
  • Polymerase Chain Reaction / methods*

Substances

  • DNA, Neoplasm