Correlation of [⁶⁸Ga]Ga-RAYZ-8009 PET/CT Uptake with Immunohistochemical Glypican-3 Expression in Hepatocellular...

Glypican-3, a cell-surface proteoglycan, is overexpressed in most hepatocellular carcinomas (HCCs). Recently, the glypican-3-targeted PET tracer [⁶⁸Ga]Ga-RAYZ-8009 was shown to enable noninvasive detection of HCC. This retrospective analysis evaluates the correlation between tumor uptake of [⁶⁸Ga]Ga-RAYZ-8009 PET/CT and glypican-3 expression, as determined by immunohistochemistry. Methods: [⁶⁸Ga]Ga-RAYZ-8009 PET/CT scans of 14 patients with histologically confirmed HCC were analyzed. Tracer uptake by HCC lesions was quantified by SUV_max and SUV_mean Glypican-3 expression was assessed by immunohistochemistry using the semiquantitative H-score. Correlations between PET/CT uptake and H-score were analyzed using Spearman rank correlation. Results: Of the 14 HCC lesions analyzed, 13 were visually positive on PET, with an SUV_mean ranging from 1.9 to 63.7 (median, 7.1) and SUV_max ranging from 3.9 to 147.9 (median, 17.7). One extrahepatic HCC lesion did not demonstrate uptake on PET or glypican-3 expression. A strong positive correlation was observed between tracer uptake and glypican-3 expression (SUV_mean: ρ = 0.72, P = 0.0048; SUV_max: ρ = 0.71, P = 0.0058). Conclusion: [⁶⁸Ga]Ga-RAYZ-8009 uptake in HCC lesions is a promising biomarker for noninvasive in vivo assessment of glypican-3 expression and may support the planning and monitoring of glypican-3-targeted therapies.