The diagnostic value of apolipoprotein E in malignant pleural effusion associated with non-small cell lung cancer

Apolipoprotein E (apoE) levels have been shown to be elevated in pleural effusion of patients with non-small cell lung cancer (NSCLC). However, the diagnostic value of apoE in pleural effusion in NSCLC has not been well validated and established.

Samples of malignant pleural effusions (MPE) and benign effusions were collected and analyzed for apoE, tumor markers, and other biochemical changes.

ApoE levels were significantly higher in MPE (n=160) than in benign pleural effusions (n=40). They were higher in adenocarcinoma-associated MPE than in squamous cell carcinoma- and large cell carcinoma-associated MPE. The receiver operating characteristic curve showed that the sensitivity and specificity of apoE for the diagnosis of MPE were 87.5% and 85.3%, respectively, at the cutoff 105 ng/ml, and the area under the curve (AUC) was 0.748. For the diagnosis of adenocarcinoma-associated MPE, apoE achieved sensitivity and specificity of 70.8% and 83.30%, respectively, and the AUC was the highest of all the markers.

ApoE levels are significantly increased in the pleural effusion of patients with NSCLC. Increased concentration of apoE in a pleural effusion is a potential marker for the diagnosis of MPE as well as for differential diagnosis of MPE in NSCLC.