CRNN and head and neck cancer: Phylogenetic analysis in mammals revealed that the CRNN gene might have evolved rapidly to defend against foreign pathogens, possibly as an adaptive evolutionary mechanism, through rounds of “arms races” of molecular changes by the pathogen and adaptations by the host [3] This evolutionary signature of resistance to foreign pathogens might be relevant to the pathogenesis of several cancers of the squamous epithelium, such as cervical cancer and head and neck cancers, that involve the Human Papilloma Virus (HPV) as an important etiological factor.