PYGO2 as an independent diagnostic marker expressed in a majority of colorectal cancers

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. Detection of CRC at the early stages of disease can play an important role in decrease of associated mortality rates. The Wnt signaling pathway is crucial for the progression of different cellular and developmental processes and Wnt pathway deregulation has been well characterized in a variety of cancers, particularly in CRC. The aim of this study was to analyze protein expression of Pygopus2 (PYGO2), the main transcription factor of Wnt pathway, in CRC tissues and evaluate its probable correlation with clinicopathological features of the patients. The expression pattern of PYGO2 was evaluated by immunohistochemistry in tumor tissues and their margin normal which is the piece of normal, or unaffected tissue excised from the surrounding the visible tumors in 46 CRC patients. A defined scoring system was applied to analyze immunostaining results. The expression of PYGO2 protein was detected in all tumor tissues. Furthermore, this expression was significantly higher in CRC samples than in normal tissues. There was a significant association between PYGO2 protein expression in CRC and tumor cell metastasis to the lymph nodes. Considering the significant expression of PYGO2 protein in colorectal tumor cells and its correlation with lymph node metastasis, this protein may be used as a biomarker for metastatic CRC as well as a putative therapeutic target to inhibit aggressiveness and metastasis of CRC.