Serum CD166: A novel biomarker for predicting nasopharyngeal carcinoma response to radiotherapy

The present study aimed to identify whether CD166 can be used as a biomarker for predicting the response of nasopharyngeal carcinoma (NPC) to radiotherapy. The serum concentration of CD166 in patients with NPC were detected by enzyme-linked immunosorbent assay. The secreted level of CD166 with radioresistant NPC was significantly higher than that with radiosensitive NPC. In vitro, the CD166 positive rate in the CNE2 cell membrane was significantly lower than that in the CNE2R cell membrane. The magnetic-activated cell sorting technology was used to obtain CNE-2R-CD166(+) and CNE-2R-CD166(-) cell lines. Then radiosensitivity, cell proliferation, and apoptosis were assessed using colony formation assay, cell counting kit 8 assay (CCK-8), and flow cytometry, respectively. The radiation sensitivity ratio was 1.28, indicating that the CNE2R-CD166(-) cells had a stronger radiation sensitivity. The result of CCK-8 assay indicated that the survival fraction of CNE2R-CD166(+) cells was significantly higher than that of CNE2R-CD166(-) cells. The apoptotic rate of CNE2R-CD166(+) cells was significantly lower than that of CNE2R-CD166(-) cells. Our data demonstrate that the secreted protein CD166 may be can used as a biomarker for predicting the response of NPC to radiotherapy.