Expression levels of APOBEC3A, APOBEC3B, APOBEC3D, APOBEC3G, and APOBEC3H in tumor specimens from cancer patients were associated with varying clinical responses to chemotherapy and with overall patient survival, and possible suggested mechanisms of such associations, which may also involve other APOBEC genes, include immune targeting of increased mutation diversity due to higher levels of APOBEC mutagenesis, associated inflammation, PD-L1 expression on tumor-infiltrating mononuclear cells, and the degree of T lymphocyte infiltration [7, 92, 97–99]. The gene discussed is APOBEC3A; the disease is neoplasm.