Figure 1. Imaging, histopathology, and mutant HIF2A signaling in the index patient. (A) Abdominal CT imaging and ultrasound revealed a hypodense and hypoechoic mass in the patient’s right liver. (B) Hematoxylin and eosin staining of the resected tumor revealed hepatocellular carcinoma, clear cell variant, with prominent angiogenesis. Tumor cells were positive for AFP and HEP and negative for CK19 by immunohistochemistry; endothelial cells stained positively for CD34. (C) Real-time PCR demonstrated overexpression of the HIF2A transcriptional targets EDN1, EPO, GNA14, and VEGFA within the tumor bed. Scale bars: 50 μm.