BAT-26 identifies sporadic colorectal cancers with mutator phenotype: a correlative study with clinico-pathological features and mutations in mismatch repair genes

J Pathol. 1999 Jul;188(3):252-7. doi: 10.1002/(SICI)1096-9896(199907)188:3<252::AID-PATH354>3.0.CO;2-3.


Microsatellite instability (MSI) is present in most colorectal cancers (CRC) associated with hereditary nonpolyposis colorectal cancer (HNPCC). MSI testing in so-called sporadic forms of CRC may become a useful tool in identifying new HNPCC kindred. The aim of this study was to analyse the utility of BAT-26 as a marker to identify CRCs with MSI and to investigate whether sporadic CRCs with MSI have a phenotypic expression similar to HNPCC cases. MSI was detected using two methods, an association of 7 poly(CA) repeats and a poly(A) repeat alone, BAT-26, in a series of 62 patients with apparently sporadic forms of CRC. Germ-line and somatic mutations in the hMSH2, hMLH1, and hMSH6 genes were analysed in patients with MSI+ tumours. Patients with MSI+ at poly(CA) loci and at BAT-26 were younger (p=0.024 and p=0.002), had tumours more frequently right sided (p=0.017 and p=0.0001) and more often mucinous (p=0.037 and p=0.005, respectively) than patients with MSI negative tumours. Mutation analysis allowed the identification of two patients carrying germ-line mutations in the hMLH1 gene (both were BAT-26+) and two other patients who had somatic mutation in the hMSH2 and in hMLH1 genes. In conclusion, the detection of MSI using poly(CA) repeats or BAT-26 alone allowed the identification of a subset of patients with clinico-pathological characteristics similar to those associated to HNPCC. BAT-26 has the advantage of being a simple and less expensive method that might be used as a screening procedure before mutation analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Base Pair Mismatch / genetics
  • Biomarkers, Tumor / analysis*
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / pathology
  • DNA Repair*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Microsatellite Repeats / genetics*
  • Middle Aged
  • Mutation*
  • Phenotype


  • Biomarkers, Tumor