Systematic identification of genes with coding microsatellites mutated in DNA mismatch repair-deficient cancer cells

Int J Cancer. 2001 Jul 1;93(1):12-9. doi: 10.1002/ijc.1299.


Microsatellite instability (MSI) caused by deficient DNA mismatch-repair functions is a hallmark of cancers associated with the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome but is also found in about 15% of all sporadic tumors. Most affected microsatellites reside in untranslated intergenic or intronic sequences. However, recently few genes with coding microsatellites were also shown to be mutational targets in MSI-positive cancers and might represent important mutation targets in their pathogenesis. The systematic identification of such genes and the analysis of their mutation frequency in MSI-positive cancers might thus reveal major clues to their functional role in MSI-associated carcinogenesis. We therefore initiated a systematic database search in 33,595 distinctly annotated human genes and identified 17,654 potentially coding mononucleotide repeats (cMNRs) and 2,028 coding dinucleotide repeats (cDNRs), which consist of n > or = 6 and n > or = 4 repeat units, respectively. Expression pattern and mutation frequency of 19 of these genes with the longest repeats were compared between DNA mismatch repair-deficient (MSI(+)) and proficient (MSS) cancer cells. Instability frequencies in these coding microsatellite genes ranged from 10% to 100% in MSI-H tumor cells, whereas MSS cancer cells did not show mutations. RT-PCR analysis further showed that most of the affected genes (10/15) were highly expressed in tumor cells. The approach outlined here identified a new set of genes frequently affected by mutations in MSI-positive tumor cells. It will lead to novel and highly specific diagnostic and therapeutic targets for microsatellite unstable cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / genetics*
  • Base Pair Mismatch / genetics
  • Base Sequence
  • Colonic Neoplasms / genetics*
  • Colorectal Neoplasms / genetics*
  • DNA Primers
  • DNA Repair / genetics*
  • DNA, Neoplasm / genetics
  • Dinucleotide Repeats / genetics
  • Humans
  • Microsatellite Repeats / genetics*
  • Mutation*
  • Rectal Neoplasms / genetics*
  • Repetitive Sequences, Nucleic Acid / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Cells, Cultured


  • DNA Primers
  • DNA, Neoplasm