SOX2 and pachyonychia congenita: The SRY (sex determining region Y)-box 2 gene, SOX2, so far recognized as crucial for the stem cell state [3] and necessary for induced cellular reprogramming [3, 4], is gaining a renewed interest as a key regulator of self-renewal and maintenance of Cancer Stem Cells (CSCs) in a variety of tumors including PC [5–10].