Glucose transporter 1 protein detected by enzyme‐linked immunosorbent assay and immunocytochemistry

Abstract

Glucose transporter 1 (GLUT1) is a hallmark of metabolic change in cancer cells. The objective of this study was to determine the role of GLUT1 protein in diagnosing malignant pleural effusions by enzyme-linked immunosorbent assay (ELISA) and immunocytochemistry. In total, 82 pleural effusions were collected and classified as benign (n = 42), atypical (n = 8), or malignant (n = 32) based on cytologic diagnosis and etiology. GLUT1 protein levels in effusions were measured by ELISA. GLUT1 expression also was determined by immunocytochemistry using cell blocks. GLUT1 levels were significantly higher in the malignant group compared with the benign group. Receiver operating characteristic curve analysis of benign and malignant pleural effusions for GLUT1 yielded an area under the curve of 0.77, with a value of 1355.87 pg/dL as the optimal threshold for distinguishing benign from malignant effusions. With the ELISA method, the sensitivity, specificity, and accuracy were 78.1%, 69%, and 73%, respectively. Malignant effusion cell blocks were positive for GLUT1 expression in 84.4% of cases with 100% specificity and 93.2% accuracy. With the combination of high GLUT1 protein levels (>10,000 pg/dL) and immunocytochemistry to detect malignant pleural effusions, the sensitivity and accuracy increased to 93.8% and 94.6%, respectively. The GLUT1 level measured by ELISA and the GLUT1 expression detected by immunocytochemistry were positively correlated. In atypical effusions, 3 cases (37.5%) had GLUT1 levels higher than the cutoff value. The detection of GLUT1 protein by ELISA and immunocytochemistry may have utility in the diagnosis of malignant pleural effusions.