Maximal standardized uptake value on FDG-PET is correlated with cyclooxygenase-2 expression in patients with lung adenocarcinoma.
BACKGROUND
Cyclooxygenase-2 (COX-2) is constitutively overexpressed in a variety of epithelial malignancies and is usually associated with a poor prognosis. Fluorodeoxyglucose positron emission tomography (FDG-PET) has become an important tool for the diagnosis and staging of non-small-cell lung cancer. The maximal standardized uptake values (SUVmax) of primary tumors on FDG-PET have been shown to be correlated with some clinicopathologic factors. In this study, we investigated the prediction of intratumoral COX-2 expression by FDG-PET in cases of lung adenocarcinoma.


METHODS
We conducted a retrospective review of the data of 60 patients with lung adenocarcinoma measuring less than 3 cm in diameter. Immunohistochemical staining for COX-2 and other biological factors that might influence cancer progression was performed, and the correlations of the selective tumor marker expression with the SUVmax were evaluated.


RESULTS
A significant correlation was observed between the SUVmax and the expressions of COX-2, Ki-67, and vascular endothelial growth factor (VEGF). Multiple stepwise regression analysis revealed significant relationships between the SUVmax and the expression of COX-2 (p<0.001) and Ki-67 (p=0.016). Of the 2, COX-2 expression was the stronger determinant of the SUVmax, which increased in proportion to the score for COX-2 expression. The recurrence-free survival of patients with elevated COX-2 expression was significantly worse than that of patients not showing COX-2 expression.


CONCLUSIONS
The expression of COX-2 in primary tumors is as strongly correlated with a worse clinical outcome as is increased FDG uptake in cases of lung adenocarcinoma. These findings indicate that the SUVmax of primary tumors might reflect the biological malignant potential in lung adenocarcinomas.
Department of General Thoracic Surgery, Kawasaki Medical School, Kurashiki, Japan. kshimizu@med.kawasaki-m.ac.jp
Katsuhiko
K
Shimizu
Yuji
Y
Hirami
Shinsuke
S
Saisho
Takuro
T
Yukawa
Ai
A
Maeda
Koichiro
K
Yasuda
Masao
M
Nakata
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000201:enzymology; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D051546:Cyclooxygenase 2 / Q000032:analysis*; D018572:Disease-Free Survival; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000032:analysis; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009363:Neoplasm Proteins / Q000032:analysis*; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging / Q000201:enzymology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D014408:Biomarkers, Tumor; D005462:Fluorine Radioisotopes; D036341:Intercellular Signaling Peptides and Proteins; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human