AICDA and squamous cell carcinoma: Genome-wide studies have shown that the most common mutational signatures observed in UADT squamous cell carcinomas are those associated with AID/APOBEC (activation-induced cytidine deaminase/apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like) activity [11,12,13], and the most common genetic alteration is TP53 mutations, leading to the inactivation of this tumor suppressor gene [14,15].