title: Introduction.
authors: Antonio
authors: A
authors: Llombart-Bosch
authors: Carlos
authors: C
authors: Monteagudo
authors: Daniel J
authors: DJ
authors: Santa Cruz
mesh_terms: D002471:Cell Transformation, Neoplastic; D020405:Dermis / Q000166:cytology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology; D008648:Mesoderm / Q000473:pathology*; D012878:Skin Neoplasms / Q000175:diagnosis*