Overexpression of Glut1 in Lymphoid Follicles Correlates with False-Positive 18F-FDG PET Results in Lung Cancer Staging

The evaluation of mediastinal lymph node involvement in non-small cell lung carcinoma (NSCLC) is very important for the selection of surgical candidates. PET using 18F-FDG has re-markably improved mediastinal staging in NSCLC. However, false 18F-FDG PET results remain a problem. This study was undertaken to identify histologic and immunohistochemical dif-ferences between cases showing false and true results of me-diastinal lymph node involvement assessed by 18F-FDG PET. Methods: Preoperative 18F-FDG PET examinations were per-formed on 62 patients with NSCLC, and mediastinal lymph node sampling was done at thoracotomy or mediastinoscopy. In 111 lymph nodes, the size, glucose transporter 1 (Glut1) expression, grade of follicular hyperplasia, and involved proportion of tumor were examined and compared with the 18F-FDG PET findings. Results: Lymphoid follicular cells were strongly positive for th