Diagnostic utility of neuron specific enolase (NSE) in serum and pleural fluids from patients with lung cancer and tuberculosis

Several past and recent investigations have focused on the determination of tumor markers in pleural fluids to assess their usefulness as less invasive replacement method of diagnosis. In this regard, few studies have dealt with the determination of the tumor marker, neuron specific enolase (NSE), in pleural fluids of patients suffering from both benign and malignant diseases such as non small cell lung carcinoma (NSCLC), small cell lung carcinoma (SCLC) and tuberculosis. Therefore, the present study was undertaken to establish the diagnostic utility of NSE in malignant condition by assessing levels in serum and pleural fluids of patients with lung cancer and by comparing it with a benign pulmonary disease of tuberculosis. Pleural fluids were obtained from 22 patients with carcinomatous pleurisy due to SCLC, 11 patients with carcinomatous pleurisy due to non-small cell lung cancer, and 30 patients with tuberculosis pleurisy for comparison purpose. Determination of NSE levels was performed by ECL technology according to the manufacturer’s instructions. NSE levels of pleural fluids from SCLC patients were significantly elevated (P<0.0001) when compared with pleural fluids from NSCLC and tuberculosis patients. Moreover, pleural fluids of all 30 tuberculosis patients and 11 NSCLC patients showed moderate significance (P<0.05 and P < 0.01, respectively) when compared with each other. In addition, cumulative results of NSE levels from SCLC and NSCLC combined also showed high significance (P<0.001) as compared to pleural fluids of tuberculosis patients and moderate significance (P<0.01) when compared with serum levels of both malignant and benign groups. It is concluded that determination of NSE levels in pleural fluids of lung cancer patients noted to be an effective diagnostic tool to differentiate carcinomatous pleurisy due to SCLC from those occurring due to NSCLC and tuberculosis. Further studies with larger group of patients are under progress to further establish and strengthen its diagnostic specificity and sensitivity.