The Percentage of Stained Cells is a More Reliable Parameter in Immunohistochemical Analysis than Scoring the Intensity of Staining: Expression of 9 Molecular Markers in Progression and Liver Metastases of Colorectal Cancer

Abstract

Aims: Research for reliable molecular markers that provide prognostic and predictive information in colorectal cancer (CRC) is based on solid evidence that the staging system on its own cannot definitively predict the tumor behavior and guide clinical management of the disease. Methods and results: In this study we examined the immunohistochemical expression of 9 markers, namely membrane-bound mucin 1 (MUC1), paxillin (PAX), Focal Adhesion Kinase (FAK), G-protein coupled receptor 56 (GPR56), ORAI3 and well known markers of colon carcinoma microsatellite instability (MSI): MSH2, MSH6, MLH1 and PMS2 with respect to the percentage of stained cells and intensity score in colon carcinoma cells, both in the primary tumor and liver metastasis. We have related all of the mentioned markers with clinicopathological data, including the age of patients, grading of the primary tumor and TNM system. Western blotting assay was performed to identify the expression. Our present study showed that the evaluation of different markers with respect to intensity of staining and percentage of stained cancer cells may be considered as a prognostic marker for tumor progression and later for liver metastasis. This has been found for the percentage of stained cells particularly. Conclusions: Our results implicate that the counting percentage of stained colon cancer cells provides a more adequate method of immunohistochemical analysis than evaluation of the intensity of staining.