Prognostic implications of BAX protein expression and microsatellite instability in all non-metastatic stages of primary colon cancer treated by surgery alone.
OBJECTIVE
This study examined whether the apoptosis-related protein, BAX, or the microsatellite-instability phenotype provide prognostic information in patients with resected colon cancer.


METHODS
A total of 371 stage I-III patients that previously underwent radical surgery were included (mean follow-up 51.8 months). BAX expression was examined by immunohistochemical staining; high-frequency microsatellite instability (MSI+) was determined by assessing the specific marker, BAT26, using single-strand conformation polymorphism (SSCP)-based analysis.


RESULTS
High BAX expression was found in 66.4% of patients. MSI+ tumors were observed in 14.8% of 344 patients. Univariate analysis showed that unlike MSI, low BAX expression was significantly correlated with poor disease-specific overall survival (OS) in stages I-III (p = 0.04). Multivariate subgroup analyses revealed that unlike MSI, low BAX was an independent predictor for OS in stage II (p = 0.009); however, in stages I or III, BAX or MSI were not independent predictors of OS.


CONCLUSIONS
In stage II colon cancer treated with surgery alone, BAX protein expression may be a predictor for prognosis.
Nehls
Oliver
O
Department of Internal Medicine I, University Hospital, 72076, Tübingen, Germany. oliver.nehls@med.uni-tuebingen.de
Hass
Holger G
HG
Okech
Thomas
T
Zenner
Silke
S
Hsieh
Chih-Jen
CJ
Sarbia
Mario
M
Borchard
Franz
F
Gruenagel
Hans-Helmut
HH
Gaco
Vera
V
Porschen
Rainer
R
Gregor
Michael
M
Klump
Bodo
B
D000368:Aged; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D010641:Phenotype; D011379:Prognosis; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
D051028:bcl-2-Associated X Protein