Neuron-specific enolase and lung cancer

Serum and bronchoalveolar lavage fluid (BALF) neuron-specific enolase (NSE) levels in lung cancer have been investigated widely; however, their diagnostic values have not yet been clarified. The authors investigated the diagnostic validity of NSE in BALF and serum in lung cancer. In this prospective case-control study, NSE levels in BALF (B-NSE) and serum (S-NSE) of 3 groups of subjects were analyzed: control subjects (group 1, n = 15), patients with chronic obstructive pulmonary disease (COPD; group 2, n = 15), and lung cancer (group 3, n = 35). The differences in S-NSE and B-NSE levels between the groups were not significant (P > 0.05). S-NSE and B-NSE levels did not show any difference between smokers and nonsmokers, small cell lung cancer and nonsmall cell lung cancer patients, and stage I-II and stage III-IV patients in group 3 (P > 0.05). B-NSE or B-NSE/urea did not show any significance in comparison with S-NSE in the diagnosis and/or staging of malignancy (P > 0.05). S-NSE and B-NSE were well correlated with each other (r = 0.84, P = 0.000). The sensitivity of the S-NSE was 60% and the specificity was 40%. The authors conclude that, although elevation of B-NSE is a well-known parameter in small cell lung cancer, it can also be elevated considerably in nonsmall cell lung cancer and COPD. Because of the significant correlation between S-NSE and B-NSE, it may be sufficient to measure S-NSE activity because it is easier and less invasive. However, NSE has no role in the exact diagnosis of lung cancer; it can only be investigated in a scientific setting.