Monitoring a ‘metabolic shift’ after surgical resection of oral squamous cell carcinomas by serum lactate dehydrogenase

ObjectivesMonitoring surgical removal of oral squamous cell carcinomas (OSCC) is being routinely performed through clinical and imaging follow‐up. We analyzed the potential use of serum lactate, lactate dehydrogenase (LDH), and LDH isoenzymes (LDH 1‐5) as biomarkers in blood for the monitoring of surgical removal of OSCC.Materials and MethodsSerum lactate, LDH, and LDH isoenzymes (LDH 1‐5) have been prospectively assessed in healthy individuals (n = 19), patients with OSCC (n = 34: primary OSCC, n = 32 and recurrent OSCC, n = 2) before surgery and after curative tumor resection (n = 26). LDHA and LDHB expressions were analyzed by immunohistochemistry (IHC) in the same OSCC tumor specimen.ResultsPositive LDHA tumor tissue expression measured by IHC (n = 34/34, 100%) was significantly associated with increased serum LDH‐5 (n = 24/34, 71%, P = 0.0258) but weak significantly associated with increased total serum LDH (n = 23/34, 68%, P = 0.0592). Positive LDHB tumor tissue expression measured by IHC (n = 25/34, 74%) was significantly associated with increased total serum LDH (P = 0.0172). After surgery, serum LDH and LDH‐5 isoenzyme significantly decreased and LDH‐1 significantly increased in the aftercare. A significantly inverse correlation of LDHA with LDHB IHC scores was found (P < 0.0001).ConclusionsThe association of LDHA and LDHB measured by IHC with serum LDH indicates that analyzing this enzyme could serve as a favorable ‘liquid biopsy’ (non‐invasive diagnostic tool) for OSCC.