CD4 and hepatocellular carcinoma: For instance, the human papillomavirus (HPV) E6 and E7 oncogenes appear to contribute to activation of β-catenin signaling in HPV16-positive oropharyngeal squamous carcinoma cells, the hepatitis C virus (HCV)-encoded core protein potentiates Wnt/β-catenin signaling in hepatocellular carcinoma cells (32, 33), and pharmacological activation of the β-catenin/TCF1 pathway with glycogen synthase kinase-3 (GSK-3) inhibitors reactivates latent HIV-1 in CD4+ T cells (34).