title: Simplified MSI marker panel for diagnosis of colorectal cancer.
abstract: BACKGROUND
  Colorectal cancers (CRCs) tumors are diagnosed by microsatellite instability (MSI) due to accumulation of insertion/deletion mutations in tandem repeats of short DNA motifs (1-6 bp) called microsatellites. Microsatellite instability (MSI) is not only a hallmark marker for screening of hereditary nonpolyposis colorectal cancer (HNPCC), but also a prognostic and predictive marker for sporadic colorectal cancer. Our objective was to determine and study of five mononucleotide microsatellite markers status among Iranian patients with HNPCC and sporadic colorectal cancer.
  
  
  METHODS
  In the current investigation 80 sporadic CRC and 80 HNPCC patients were evaluated for MSI. The pentaplex panel including 5 quasimonomorphic mononucleotide repeats (NR-21, BAT-26, BAT-25, NR-27 and NR-24) was used.
  
  
  RESULTS
  Our findings showed that the NR-21 was the most frequent instable marker among the other markers. 53% and 25.6% specimens had instability in sporadic CRC and HNPCC, respectively. Furthermore, the frequencies of instability BAT-25 was determined in 20% sporadic CRC and 23% HNPCC samples. Interestingly our results demonstrated that the frequency of instability NR-24 was similar 20% sporadic CRC and 20.5% HNPCC. Moreover, percentage of NR-27 in HNPCC was 19.2 and 0% in sporadic CRC. Finally, BAT-26 was instable in 21.8% HNPCC patients while we could find 6.6% instability for BAT-26 in sporadic cases.
  
  
  CONCLUSIONS
  It seems that among 5 mononucleotides markers NR-21 was the most useful marker for diagnosis HNPCC and sporadic cancer. Following NR-21, BAT-25 and NR-24 are the most reliable markers. Therefore using a triplex panel including 3 aforementioned MSI markers should be more promising markers for identifying MSI status in both patients with HNPCC and/or sporadic colorectal cancer.
authors.affiliation: Research Center for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Atena Irani
authors.initials: AI
authors.lastname: Shemirani
authors.forename: Mahdi Montazer
authors.initials: MM
authors.lastname: Haghighi
authors.forename: Saman Milani
authors.initials: SM
authors.lastname: Zadeh
authors.forename: Seyed Reza
authors.initials: SR
authors.lastname: Fatemi
authors.forename: Mohammah Yaghoob
authors.initials: MY
authors.lastname: Taleghani
authors.forename: Narges
authors.initials: N
authors.lastname: Zali
authors.forename: Zahra
authors.initials: Z
authors.lastname: Akbari
authors.forename: Seyed Mohammad Hossein
authors.initials: SM
authors.lastname: Kashfi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zali
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D053842:Microsatellite Instability; D018895:Microsatellite Repeats; D011379:Prognosis; D020080:Tandem Repeat Sequences
chemical_list: D014408:Biomarkers, Tumor