FDG uptake and glucose transporter type 1 expression in lymph nodes of non-small cell lung cancer

AimsFDG uptake in NSCLC is related to glucose transporter type 1 (Glut-1) expression. Here, we investigated the direct causal relationship between FDG uptake and Glut-1 expression to determine the role of Glut-1 in FDG uptake by malignant and benign lymph nodes (LNs).MethodsFifty-five curative lung resections in 53 NSCLC patients (male:female = 36:17, age = 62.0 ± 11.8 years) were included. Maximum standardized uptake values (maxSUVs) of LNs in preoperative whole body FDG-PET and Glut-1 immunostaining results were compared.ResultsOf 316 pathologically confirmed LNs, 12.3% (39/316) were malignant, and in malignant LNs, FDG positive LNs were no different from FDG negative LNs in terms of size (15.0 ± 6.7 mm vs 10.0 ± 6.1 mm, p > 0.05), or in terms of the proportion of LNs occupied by tumor (60.0 ± 28.8% vs 39.2 ± 38.4%, p > 0.05), but had greater percentages of Glut-1 positive cells in tumors (74.1 ± 31.8% vs 22.7 ± 18.7%, p < 0.01), and Glut-1 staining intensities (3.4 ± 0.9 vs 1.8 ± 1.3, p < 0.01). FDG negative malignant LNs featured cytoplasmic Glut-1 expression and adenocarcinoma. Glut-1 staining intensities were found to be significantly correlated with the maxSUVs of malignant LNs (ρ = 0.516, p < 0.05), but the percentages of Glut-1 positive cells in tumors were not (r = 0.2072, p > 0.05). Analysis of FDG positive benign LNs showed that maxSUV was not correlated with degree of follicular hyperplasia, or Glut-1 expression (p > 0.05).ConclusionsIntense Glut-1 immunoreactivity was found to be proportionally related to the degree of FDG uptake by malignant LNs in NSCLC. However, the finding that Glut-1 expression in lymphoid hyperplasia showed no correlation with FDG uptake in benign LNs requires further investigation.