[Microsatellite instability predicts better outcome in colorectal cancer patients].
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.
Vidaurreta
Marta
M
Servicio de Análisis Clínicos, Sección Biología Tumoral, Hospital San Carlos, Madrid, Spain.
Sanz-Casla
María Teresa
MT
Maestro
María Luisa
ML
Rafael
Sara
S
Jiménez
Fernando
F
Arroyo
Manuel
M
Fernández
Cristina
C
Cerdán
Javier
J
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