FAK, CD44v6, c-Met and EGFR in colorectal cancer parameters: tumour progression, metastasis, patient survival and receptor crosstalk

Abstract

Research for reliable and patient-specific markers in colorectal cancer (CRC) is based on solid evidence that staging alone is not informative enough. Employing four cellular receptors, we embarked to identify aggressive tumour behaviour and impact of surrogate marker expression on patient prognosis. One-hundred eighty-three CRC patients were enrolled in our investigation that focused on an array of biological markers, namely epidermal growth factor receptor (EGFR), c-Met, focal adhesion kinase (FAK) and CD44v6. Tissue samples, clinicopathological data and patient's follow-up information were collected, and immunohistochemical assays evaluated the levels of the aforementioned molecules. All available data were correlated with tumour grade, stage, patient age, gender and survival. Expression of all receptors correlated closely with tumour stage (P < 0.01) exhibiting a connection with cancer's invasiveness and progress. Survival also proved to depend significantly on molecular expression (log-rank test for Kaplan-Meier; EGFR P = 0.030, c-Met P = 0.050, FAK P < 0.001, CD44v6 P < 0.001). Stage, FAK and CD44v6 emerged as independent predictors of survival in a stepwise regression analysis (FAK P = 0.001 Exp(B) = 2.517, 95% confidence interval (CI) = 1.704-5.831 and CD44v6 P = 0.005, Exp(B) = 2.299, 95% CI = 1.287-4.110). T-stage, nodal metastasis, all metastatic types (N/M) and size correlated with at least one of the receptors or their co-expression. Notably, increased staining for each receptor was followed by statistically significant expression elevation of at least one of the other markers. Our results suggest that the selected cellular receptors are suitable for use as biomarkers of survival and tumour progression in CRC. Furthermore, we provide additional evidence for receptor interaction, properly clarifying their importance, which could potentially lead to more effective anti-CRC regimens.