Evaluation of a biomarker based blood test for monitoring surgical resection of oral squamous cell carcinomas

Introduction The potential use of determination of biomarkers in blood for the monitoring of surgical removal of oral squamous cell carcinomas (OSCC) was evaluated using the epitope detection in monocytes (EDIM) technology. Materials and methods In tumor specimen, elevated Apo10 and transketolase-like 1 (TKTL1) expression was analyzed by immunohistochemistry. Apo10 and TKTL1 biomarkers have been used prospectively for EDIM blood test in patients with primary and/or recurrent OSCC (n = 92) before surgery and after curative tumor resection (n = 45). Results There were highly significant (p < 0.0001) correlations found between EDIM blood scores and the tissue expression of both biomarkers measured by immunohistochemistry (Apo10: n = 89/92, 97 %; TKTL1: n = 90/92, 98%). EDIM Apo10 and EDIM-TKTL1 scores were positive in 92 % (EDIM-Apo10: n = 85/92) and 93 % (EDIM-TKTL1: n = 86/92), respectively, in patients with OSCC before surgery. The combined score EDIM-Apo10/EDIM-TKTL1 increased significantly the detection rate of tumors to 97 % (n = 89/92). After surgery, the EDIM-TKTL1 and EDIM Apo10 scores significantly decreased in 75.6 and 86.7 % of the patients (p < 0.0001), respectively, in the aftercare. Conclusions The correlation of TKTL1 and Apo10 immunohistochemistry with the blood test results indicates that the EDIM blood test could serve as a non-invasive diagnostic tool (liquid biopsy) to assess surgical removal of OSCC by determination of two biomarkers. Clinical relevance This is the first study that has been demonstrated a reliable and successful monitoring of OSCC cancer patients by a blood test. The specific and significant decrease of EDIM-TKTL1 and EDIM-Apo10 scores after surgery could serve as a new tool for monitoring surgical removal of OSCC.