Biologic correlates of ¹⁸F-FDG uptake on PET in pulmonary pleomorphic carcinoma

Background: Pulmonary pleomorphic carcinoma is a rare epithelial tumor, and little is also known about the information on the usefulness of 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography (PET). Therefore, we conducted the study including the underlying biologic analysis of ¹⁸F-FDG uptake.

Methods: Fifteen patients with pulmonary pleomorphic carcinoma who underwent ¹⁸F-FDG PET before treatment were included in this study. Tumor sections were stained by immunohistochemistry for glucose transporter 1 (Glut1); glucose transporter 3 (Glut3); hypoxia-inducible factor-1 alpha (HIF-1α); cell proliferation (Ki-67 labeling index); vascular endothelial growth factor (VEGF); microvessels (CD34); cell cycle control marker (p53); and apoptosis marker (bcl-2). These parameters were correlated with a control group of patients with other non-small cell lung cancer (NSCLC) (n=33).

Results: The maximal standardized uptake value (SUV(max)) of the primary tumors in 15 patients ranged from 6.1 to 26.8 (median 19.3). There were positive correlation between ¹⁸F-FDG uptake and Glut1 (p=0.0016), Glut3 (p=0.0080), VEGF (p=0.0048), and microvessel density (MVD) (p=0.0005). HIF-1α, p53 and bcl-2 showed no positive correlation with ¹⁸F-FDG uptake. ¹⁸F-FDG uptake, Glut1, Glut3, HIF-1α, VEGF and Ki-67 were significantly higher in patients with pulmonary pleomorphic carcinoma than those with other NSCLC.

Conclusion: ¹⁸F-FDG uptake in pulmonary pleomorphic carcinoma is closely associated with the presence of glucose metabolism (Glut1 and Glut3) and angiogenesis (VEGF and MVD). The relationship between ¹⁸F-FDG uptake and these biomarkers may lead to a more rational use of PET scan in pulmonary pleomorphic carcinoma.