title: Clinicopathological features of non-familial colorectal cancer with high-frequency microsatellite instability.
abstract: OBJECTIVE
  To explore the clinicopathological features of non-familial colorectal cancer with high-frequency microsatellite instability (MSI-H).
  
  
  METHODS
  One hundred and fifty patients with colorectal cancer who had no family history were enrolled in this study from June 2006 to June 2008. Five standard microsatellite loci including BAT25, BAT26, D2S123, D5S346, and D17S250 were amplified with immunofluorescent polymerase chain reaction. The patient information including age, sex, and tumor location was recorded. Pathological features including differentiation, mucinous differentiation, histological heterogeneity, and Crohn's-like reaction were observed under light microscope. The presence of tumor-infiltrating lymphocytes (TLs, CD4+ and CD8+) was detected by means of immunohistochemistry. A regression equation was obtained by stepwise logistic regression analysis to evaluate the relationship between MSI-H phenotype in colorectal cancer and pathological features.
  
  
  RESULTS
  MSI-H phenotype occurred in 13.33% of the 150 patients with non-familial colorectal cancer. Poor differentiation, histological heterogeneity, Crohn's-like reaction, and presence of TLs were found to be independent factors to identify MSI-H non-familial colorectal cancer. Logistic regression equation showed an overall sensitivity of 70.0%, specificity of 99.2%, and accuracy of 95.3% in identifying MSI-H non-familial colorectal cancer.
  
  
  CONCLUSIONS
  MSI-H non-familial colorectal cancer manifests specific pathological features, which may be relied upon for effective identification of that disease.
authors.affiliation: Department of Gastroenterology, The Military General Hospital of Beijing, Beijing 100700, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Peng
authors.forename: Meng
authors.initials: M
authors.lastname: Xiao-ming
authors.forename: Sheng
authors.initials: S
authors.lastname: Jian-qiu
authors.forename: Wu
authors.initials: W
authors.lastname: Zi-tao
authors.forename: Fu
authors.initials: F
authors.lastname: Lei
authors.forename: An
authors.initials: A
authors.lastname: He-juan
authors.forename: Han
authors.initials: H
authors.lastname: Ying
authors.forename: Li
authors.initials: L
authors.lastname: Shi-rong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D015179:Colorectal Neoplasms / Q000235:genetics*; D017931:DNA Primers; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016015:Logistic Models; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D008875:Middle Aged; D010641:Phenotype; D016133:Polymerase Chain Reaction
chemical_list: D017931:DNA Primers