68Ga-Prostate-Specific Membrane Antigen Uptake as a Surrogate Biomarker of Neovascularity in Hepatocellular Carcinoma

Abstract

⁶⁸Ga-prostate-specific membrane antigen (⁶⁸Ga-PSMA) is expressed in the endothelium of tumor-associated neovasculature of various solid malignancies possibly due to tumor-associated angiogenic factors and endothelial cell sprouting. We report a case of a 45-year-old man with known colorectal cancer, cirrhosis, and hepatitis C. Contrast-enhanced computed tomography (CT) showed a hypervascular lesion in the liver, and ¹⁸F-fluorodeoxyglucose positron emission tomography (PET) did not show any suspicious hepatic uptake. ⁶⁸Ga-PSMA PET-CT showed predominantly heterogeneous perilesional uptake in a configuration similar to the arterial enhancement pattern on the diagnostic CT. ⁶⁸Ga-PSMA uptake in hepatocellular carcinoma appears to be primarily neoangiogenesis driven, and its morphological and functional characterization can subsequently influence the selection of anti-neoangiogenic chemotherapy agents as well as guiding radionuclide ligand therapy.

Keywords: 68Ga-prostate-specific membrane antigen positron emission tomography/computed tomography; angiogenesis; hepatocellular carcinoma; positron emission tomography/computed tomography.

Figure 1

a) FDG MIP and b-d) Transaxial FDG PET-CT images show no abnormal FDG localization in the liver. Triple phase i) un-enhanced j) arterial and k) venous CT images showed a large predominantly arterial enhancing lesion in segment VII with imaging features of Hepatocellular Carcinoma (HCC) e) 68Ga-PSMA MIP f-h) Transaxial 68Ga-PSMA PET-CT images show heterogenous increase tracer uptake in segment VII in a peripheral pattern closely resembling pattern of enhancement on arterial phase imaging (j)