BACKGROUND: Colorectal cancer is one of the most common causes of death for malignant neoplasm in the Occidental World, corresponding colorectal adenocarcinoma to represent more than 90% of malignant tumors in large bowel. Caspase-3 cysteine protease, one of the most important enzymes related in the apoptosis process, may be used as a tumor marker. AIM: To identify and quantify Caspase-3 expression in colorectal adenocarcinoma samples and to correlate the marker expression using an image computerized analysis system. METHOD: Caspase-3 expressions were studied by immunohistochemistry in 55 colorectal adenocarcinoma sampled-tissues, prepared in paraffin blocks. SAMBA 4000 System was used for the immunostained tissues analysis. Microscopic evaluation was performed by the IMUNNO 4.00 software, which analyzed 8 to 10 fields in order to determine two parameters: Labeling Index (LI), indicating the percentage of cells specifically stained by immunohistochemistry, and Mean Optical Density (MOD), representing enhance intensity, measured by positive pixels. For the statistical analysis, t-Student test and Pearson coefficient verified the possible correlation concerning LI and MOD. RESULTS: All samples presented positivity for Caspase-3 expression (LI 85,24% ± 8,71% positive cells). Caspase-3 expression revealed statistically significance correlation between LI and MOD (P = 0,013). CONCLUSIONS: The intensity of Caspase-3 expression and the number of positive cells expressing such a marker showed a positive and significant correlation.
Colorectal adenocarcinoma; Ki-67; Caspase-3; SAMBA 4000
