In the mouse prostate, KRT7 was recently described as a novel prostate progenitor marker, and authors have suggested that label-retaining stem cells co-expressing candidate stem cell markers (such as SCA-1, TROP-2, CD133, CD44, c-KIT, and KRT7) could function as cancer-initiating and relapse-driver cells in murine PC [21]. The gene discussed is KRT7; the disease is pachyonychia congenita.