RIPK4 and cutaneous squamous cell carcinoma: By large-scale genomic sequencing analysis, RIPK4 mutations have been identified in cutaneous squamous cell carcinoma (SCC), esophageal SCC, human papillomavirus (HPV)-positive oral SCC, and head and neck SCC, implicating a critical function of RIPK4 in squamous differentiation and carcinogenesis (Stransky et al., 2011; Li et al., 2018; Gillison et al., 2019; Pickering et al., 2014; Li et al., 2015).