These findings suggest that changes in the expression of genes associated with the TGF-β signaling pathway, specifically CDKN2B, GRB2, and PIK3R1, in CTCs may be biomarkers reflecting treatment response earlier and more accurately than changes in CTC count in patients with HCC treated with Atezo+Bev. The gene discussed is PIK3R1; the disease is hepatocellular carcinoma.