In mammals, several cytidine deaminases work on DNA, with AID being important in modulation of immunoglobulin genes in somatic hypermutation and class switch recombination—processes needed for generation of high-affinity antibodies [3], whereas the APOBEC catalytic subunit 3A (A3A) and APOBEC catalytic subunit 3B (A3B) enzymes function in tumour restriction and evolution [2]. This evidence concerns the gene AICDA and neoplasm.