Application of proximity ligation assays to identify potential plasma biomarkers in oral cavity cancer patients: A case control study

BACKGROUND Practical cancer biomarkers for oral cavity cancer are currently in limited use. OBJECTIVE We aimed to investigate the differences in soluble E-cadherin between patients with oral cavity cancer and matched healthy participants via Proximity Ligation Assay (PLA). METHODS Samples were taken from both patients diagnosed with oral cavity cancer, as well as non-cancerous participants. PLA was used to detect soluble E-cadherin and Cycle threshold (Ct) values derived from qPCR in order to calculate the number of starting amplicons. RESULTS In total, 74 patients with oral cavity cancer and 55 matched non-cancerous participants were included for final analysis. The Ct value of E-cadherin was found to be lower in oral cavity cancer patients when compared with that of the matched non-cancerous participants (20.72 ± 0.39 versus 21.27 ± 0.45, P< 0.001). Using a Ct value of 20.9 as a cut-off point, the sensitivity and specificity of discriminating patients with oral cavity cancer from the healthy controls was 63.5% and 87.3%, respectively. CONCLUSION Plasma soluble E-cadherin levels were significantly higher in patients with oral cavity cancer when compared with those from the matched non-cancerous participants.