Identification of mannose receptor and CD163 as novel biomarkers for colorectal cancer

The aim of present study was to investigate the clinical significances of mannose receptor (MR) and CD163 in colorectal cancer (CRC). Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) were utilized for this analysis. Preoperative serum MR and CD163 levels ranged from 0.153 to 0.804 μg/ml (median = 0.359 μg/ml) and from 0.319 to 1.314 μg/ml (median = 0.685 μg/ml) in CRC patients respectively. Strikingly, preoperative serum levels of MR and CD163 were significantly increased in CRC patients than in healthy individuals (P< 0.0001). ROC analyses suggested that the optimum diagnostic cut-offs for serum MR and CD163 were 0.3485 μg/ml (AUC 0.7205, sensitivity 54.82%, and specificity 80.46%) and 0.6111 μg/ml (AUC 0.7463, sensitivity 62.65%, and specificity 80.46%) respectively. Detection of serum MR and CD163 together obviously enhanced the diagnostic accuracy (AUC 0.7968, sensitivity 69.28%, and specificity 77.01%). Then, preoperative serum MR and CD163 levels correlated significantly with serum CEA, CA19-9 and CA72-4 concentrations in CRC patients (P< 0.05). High MR and CD163 expression in serum was associated significantly with shorter overall survival (P< 0.05) and demonstrated as adversely prognostic factors (P< 0.05). Further, expression of MR and CD163 in CRC tissues was significantly higher than that in para-cancer tissues (P< 0.001). High expression of MR and CD163 in CRC tissues also correlated significantly with shorter overall survival (P< 0.05). MR and CD163 expression in serum or CRC tissues all correlated positively with the degree of lymphatic metastasis (P< 0.0001). In conclusion, MR and CD163 may be novel biomarkers for CRC patients.