CD8A and hepatocellular carcinoma: Based on the fact that Alpha-fetoprotein (AFP) is highly expressed in HCC, it constitutes not only a specific biomarker for HCC diagnosis, but also a target for immunotherapy, such as in the case of AFP-based HCC vaccines that provided a weak anti-tumor effect compared to optimized AFP gene vaccine, which demonstrated an increased AFP-specific CD8 effectors’ response and it proved protective for mice against AFP positive tumor cell challenge [111,121].