MSLN and neoplasm: In 18F-2-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography/computed tomography imaging performed to monitor the metabolic active volume (MAV) of individual tumor lesions, the total MAV remained stable in three patients and decreased by 69.2% in one patient with biopsy-proven mesothelin expression; in this patient, all liver lesions showed complete abrogation of FDG uptake at 1 month as compared to the baseline.