LGR5 Expression in Lymph Node Metastases of Colorectal Cancer: Clinicopathological Insights and Prognostic Implications

Abstract LGR5 is a promising cancer stem cell marker in colorectal cancer (CRC), and many studies have been conducted on primary tumors. However, LGR5 expression in lymph nodes has not been well studied. In this study, we identified LGR5 expression by RNAscope, a highly sensitive RNA in situ method, and analyzed its association with clinicopathological characteristics. Tissue microarrays were generated from primary tumors and lymph node metastases in paraffin-embedded blocks of 38 CRC surgical resection materials. LGR5 expression by RNAscope was evaluated by dividing the expression levels into negative and positive expression. In all but two cases of lymph node metastasis, LGR5 -positive dots were detected in tumor cells, and there was a wide range of LGR5 -positive cells. More LGR5 -positive dots were identified in the gland-forming region. Twenty-three cases were classified into an high LGR5 -expression group, and 15 cases were classified into an low LGR5 -expression group. In the high LGR5 -expression group, the histological grade was lower than in the low LGR5 -expression group (P = 0.0159), while necrosis was significantly more prevalent (P = 0.0326), and the TNM stage was significantly lower (P = 0.0302). There was no association between LGR5 expression levels in lymph node metastases and LGR5 expression levels in primary tumor tissue. LGR5 expression in lymph node metastases may influence prognosis. Further analysis may lead to new therapeutic strategies.