Immunohistochemistry corroborated the molecular data and demonstrated distinct SOX2 expression in the basal cell layer of normal prostate glands (as previously reported in ref. 13) and its absence in most of the neoplastic epithelia (Figure 1B), with the exception of a few low-grade foci (10/75:13%) and a discrete number of high-grade PC foci (47/131: 36%). The gene discussed is SOX2; the disease is pachyonychia congenita.