title: [Microsatellite instability predicts better outcome in colorectal cancer patients].
abstract: OBJECTIVE
  Two different pathways for the development of tumor have been described in colorectal carcinoma: the chromosomic instability, raised by suppressor genes and proto-oncogene alterations, and the microsatellite instability (MSI), caused by alterations in DNA repairing genes.
  
  
  METHODS
  The frequency and the clinical meaning of the microsatellites instability pathway were determined in a consecutive prospective cohort of 106 patients who underwent surgical resection of colorectal carcinoma by a single surgeon. Microsatellite instability determination was established according to the criteria proposed by the National Cancer Institute in 1998.
  
  
  RESULTS
  9.4% of patients had a high instability and it was low in 11.3%; both groups displayed different clinico-pathological characteristics (age, sex, tumor site and histologic type). In the multivariant analysis of overall survival and disease free survival, high instability exhibited prognostic value independent of the rest of variables evaluated (p < 0.0001).
  
  
  CONCLUSIONS
  The genetic alterations giving rise to microsatellite instability lead to a better prognosis in patients with colorectal cancer.
authors.affiliation: Servicio de Análisis Clínicos, Sección Biología Tumoral, Hospital San Carlos, Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Vidaurreta
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Sanz-Casla
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Maestro
authors.forename: Sara
authors.initials: S
authors.lastname: Rafael
authors.forename: Fernando
authors.initials: F
authors.lastname: Jiménez
authors.forename: Manuel
authors.initials: M
authors.lastname: Arroyo
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernández
authors.forename: Javier
authors.initials: J
authors.lastname: Cerdán
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000401:mortality; D000368:Aged; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000401:mortality*; D005260:Female; D042822:Genomic Instability; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D011379:Prognosis; D000090063:Proto-Oncogene Mas; D016019:Survival Analysis