Previous studies on the prognostic value of osteopontin (OPN) and β-catenin in colorectal carcinoma (CRC) revealed conflicting results. To date, only two immunohistochemical studies investigated their association in CRC with discrepant results. Moreover, the relevance of their co-expression to clinicopathological parameters was not previously reported. This study was designed to investigate the relationship between these markers and prognostic parameters in CRC and study further the relationship between them. Immunohistochemical expression of OPN and β-catenin was evaluated in 72 CRCs. Cytoplasmic OPN was detected in 45.83% of CRCs while normal mucosa was immunonegative. Strong continuous membranous β-catenin was present in normal mucosa. However, abnormal membranous, nuclear and cytoplasmic expressions were observed in 36.11%, 31.94% and 52.78% of CRCs, respectively. A highly significant relationship was detected between each of OPN and nuclear β-catenin expression and lymph node metastasis (P = 0.0001 and 0.004 respectively), depth of invasion (P = 0.001 and 0.004 respectively), TNM stages (P = 0.0001 and 0.001 respectively) and Dukes' stages (P = 0.0001 and 0.004 respectively). A significant association was found between OPN and distant metastases. A strong agreement was observed between OPN and nuclear β-catenin (kappa = 0.656). A highly significant relationship was found between their co-expression and poor prognostic parameters. OPN overexpression and nuclear β-catenin expression appeared to be associated with unfavorable prognostic factors in CRC. A direct relationship was observed between them. Further understanding their role in colorectal carcinogenesis as well as targeting the interaction between them might be effective in the future development of therapeutic agents for CRC patients.
Keywords: Colorectal carcinoma; immunohistochemistry; osteopontin; β-catenin.