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.