Value of the identification of microsatellite instability in colorectal cancer.
OBJECTIVE
Recent studies defend a possible prognostic and therapeutic value of the identification of microsatellite instability (MSI) in colorectal cancer. This work tries to assess the impact that the identification of MSI tumours can have in clinical practice.


METHODS
We recovered tumour samples from 92 of the 143 patients operated on for colorectal cancer in our institution between 1995 and 2000. Five MSI markers (BAT 25, BAT 26, D2S123, D5S346 and D17S250) were studied on them. The rate and clinicopathologic characteristics of MSI tumours were investigated along with their impact on the global and disease-free survival as compared with microsatellite stable (MSS) tumours.


RESULTS
All 5 microsatellite markers' status were established in 73 patients (79.3% of the samples). Among them, 7 tumours showed instability in just one marker (low microsatellite instability [MSI-L]) whereas 5 tumours had mutations in 2 or more markers (high microsatellite instability [MSI-H]), for a total 15.4% rate of MSI tumours. All MSI-H tumours were located in the right colon. We could not fi nd any impact from MSI detection on global or disease-free survival.


CONCLUSIONS
MSI determination did not identify groups of patients with a different prognosis. Moreover, with such low incidence its determination can only be justified in those cases that fulfill Bethesda's criteria to identify families with Lynch's syndrome.
Barrasa Shaw
Antonio
A
General Surgery Department, Fundación Instituto Valenciano de Oncología, Valencia, Spain. antoniobarrasa@aecirujanos.es
López-Guerrero
José Antonio
JA
Calatrava Fons
Ana
A
García-Casado
Zaida
Z
Alapont Olavarrieta
Vicente
V
Campos Máñez
Jorge
J
Vázquez Albaladejo
Carlos
C
D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D011379:Prognosis
D014408:Biomarkers, Tumor