Prognostic Value of Immunohistochemical Expressions of the Stem Cell Biomarker "LGR5" and the Proliferation Biomarker "TPX2" in Colorectal Carcinoma

Abstract

Aim: Colorectal carcinoma (CRC) is the commonest and most deathly malignant gastrointestinal tumors. Carcinogenic process starts in a group of cancer cells, called cancer stem cells (CSCs) having the ability to start and maintain tumor growth and invasion. In order to detect and remove colon CSCs, a selective biomarker "LGR5 (leucine-rich-repeat-containing G-protein-coupled receptor 5)" might be required. At the same time, an abnormal expression of TPX2 (targeting protein for xenopus kinesin-like protein 2) has been found to be related to the development and progression of tumors. We aimed to evaluate the immunohistochemical expressions of LGR5 and TPX2 in CRC in a trial to clarify their relations to proliferation and metastasis of CRC, and hence its prognosis. Methods: Immunohistochemical staining of both LGR5 and TPX2 was assessed in sections from sixty paraffin blocks of CRC . The relationships between their levels of expressions with the clinicopathological parameters and patient outcome were statistically analyzed. Results: The immunoexpression of LGR5 in CRC was signifi­cantly positively correlated with location of the tumor, grade, stage, local recurrence, lymph node and distant metastasis (p <0.001). The expression of TPX2 in CRC was also found to be signifi­cantly correlated with the previous parameters (p <0.001). High LGR5 and TPX2 immunohistochemical expressions were strongly correlated with worse 3-year overall survival (OS), local recurrence free survival (LRFS) and distant metastases free survival (DMFS) (P <0.001). Conclusion: High immunohistochemical expressions of both LGR5 and TPX2 and the positive correlation between both of them represent signs of poor prognosis of CRC.