TGFBR1 and squamous cell carcinoma: In other studies, one form of KA, known as Ferguson-Smith syndrome (multiple KAs, i.e., multiple self-healing squamous epitheliomas (MSSEs))—a rare, inherited skin disease that causes the development of many tumors that resemble squamous-cell carcinoma and which typically occurs in young adolescents—has been associated with a high incidence of TGFBR1 mutations, whereas SCC has shown fewer documented instances of such mutations [20,21].