Overexpression of Glut1 in lymphoid follicles correlates with false-positive (18)F-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 (18)F-FDG has remarkably improved mediastinal staging in NSCLC. However, false (18)F-FDG PET results remain a problem. This study was undertaken to identify histologic and immunohistochemical differences between cases showing false and true results of mediastinal lymph node involvement assessed by (18)F-FDG PET.


METHODS
Preoperative (18)F-FDG PET examinations were performed 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 (18)F-FDG PET findings.


RESULTS
Lymphoid follicular cells were strongly positive for the expression of Glut1. The grade of follicular hyperplasia in false-positive lymph nodes was higher than that in true-negative nodes (P < 0.001). The Glut1 expression of metastatic tumors was higher in true-positive nodes than that in false-negative nodes (P < 0.001). Metastatic squamous cell carcinomas showed stronger Glut1 expression than adenocarcinomas and no false-negative results on (18)F-FDG PET. On the other hand, metastatic adenocarcinomas exhibited focal and weak Glut1 expression with frequent false-negative results.


CONCLUSIONS
The results of this study indicate that (a). lymphoid follicular hyperplasia with Glut1 overexpression may have a causal relationship with high (18)F-FDG uptake of false-positive nodes and (b). the lower expression of Glut1 in metastatic tumors, such as adenocarcinomas, might be responsible for false-negative lymph nodes.
Chung
Jin-Haeng
JH
Department of Pathology, Korea Cancer Center Hospital, Seoul, Korea.
Cho
Kyung-Ja
KJ
Lee
Seung-Sook
SS
Baek
Hee Jong
HJ
Park
Jong-Ho
JH
Cheon
Gi Jeong
GJ
Choi
Chang-Woon
CW
Lim
Sang Moo
SM
D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000556:secondary; D003951:Diagnostic Errors / Q000517:prevention & control*; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D018858:Germinal Center / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D051272:Glucose Transporter Type 1; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008482:Mediastinum; D008875:Middle Aged; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009367:Neoplasm Staging / Q000379:methods; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; D019275:Radiopharmaceuticals; C495677:SLC2A1 protein, human; D019788:Fluorodeoxyglucose F18