Prognostic Role of EMR1 in Lymph Nodes and Primary Tumors of Colon Cancer Patients

The purpose was to investigate whether the eosinophil biomarker EMR1, ectopically expressed in colon cancer tumor cells, could be used to identify patients at risk for relapse after curative surgery. EMR1 mRNA levels were determined in primary tumors (n = 66) and lymph nodes (LNs; n = 377) from 121 colon cancer patients. Controls were resection margins of colon cancer tumors and LNs from patients with inflammatory bowel disease. Primary read-out was recurrency evaluated as disease-free survival time in the Kaplan-Meier survival model and hazard ratio calculation by uni- and multivariate Cox regression. High EMR1 levels in the regional LNs were associated with poor prognosis [hazard ratio 3.1 (1.2-8.0) at 5-year follow-up, p = 0.02]. Patients with a very poor prognosis were identified by combining EMR1 with CXCL17 analysis of LNs [hazard ratio 4.6 (1.1-19.7), p = 0.04]. High EMR1 levels in the primary tumor were associated with a good prognosis [hazard ratio 0.1 (0.02-0.9), p = 0.04]. Multivariate analysis strengthened the result for LNs but weakened the result for the primary tumor. These contradictory prognostic results probably relate to the prominent eosinophilia in the primary tumor, essentially lacking in LNs, where ectopically expressed EMR1 in tumor cells dominates. Thus, EMR1 expressed in tumor cells probably promotes tumor growth.