Single-cell landscape analysis revealed low ESR1 expression across all cell types within the HCC ecosystem (Fig. 7B), whereas APOA1, PPARGC1A, SERPINE1, and PON1 were predominantly expressed in malignant cells (Fig. 7D, 7H, 7 J, and 7L). The gene discussed is APOA1; the disease is hepatocellular carcinoma.