Expression of Liver-Type Fatty-Acid-Binding Protein, Fatty Acid Synthase and Vascular Endothelial Growth Factor in Human Lung CarcinomaKawamura T. · Kanno R. · Fujii H. · Suzuki T.
Departments of aPathology and bSurgery, Fukushima Medical University School of Medicine, Fukushima, and cDepartment of Signal Transduction, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
Objective: A key enzyme of fatty acid synthesis, fatty acid synthase (FAS), is expressed in human cancers, including squamous-cell carcinoma of the lung, and long-chain fatty acids are intracellularly transported and/or taken up from blood by fatty-acid-binding proteins (FABPs). Since the liver-type (L-) FABP, a member of the FABPs, is detected in a subset of gastric adenocarcinomas, the expression of FAS, L-FABP and vascular endothelial growth factor (VEGF) was investigated in human lung carcinomas to elucidate the mechanisms of production and transportation of fatty acid(s) in cancer. Methods: Expression of L-FABP, FAS and VEGF in 199 surgically resected lung carcinomas was examined immunohistochemically. Possible associations of the expression of each protein with major clinicopathological factors were analyzed. Results: L-FABP was detected in 60% (120 of 199) of the lung carcinoma cases; detection was increased in large-cell carcinoma (80%) and adenosquamous carcinoma (83%), but low in squamous-cell carcinoma (47%) and in small-cell carcinoma (57%). Overall expression of FAS was 67.3% (134 of 199 cases) and that of VEGF was 86.8% (158 of 199 cases), respectively. Expression of L-FABP was not correlated with the FAS status, but there was a tendency to co-expression of L-FABP and VEGF. There was no association between L-FABP, FAS or VEGF expression and clinicopathological data. Conclusions: L-FABP, FAS and VEGF are highly expressed in human lung cancer, and expression of L-FABP is associated with that of VEGF but not that of FAS, suggesting that L-FABP might be involved in the uptake of fatty acid(s) from the bloodstream.