It also remains to be determined if other molecule(s) additional to NTCP contributes to the cellular entry of HBV and/or HDV as a coreceptor(s) or receptor component(s), and if other host factors such as the microenvironment or architecture of hepatocytes in liver, or soluble blood components like those that have been shown to involve in infections of other viruses (Shayakhmetov et al., 2005; Morizono et al., 2011), contribute to HBV and/or HDV infection. The gene discussed is SLC10A1; the disease is infection.