title: Patterns in melanocytic lesions: impact of the geometry on growth and transport inside the epidermis.
abstract: In glabrous skin, nevi and melanomas exhibit pigmented stripes during clinical dermoscopic examination. They find their origin in the basal layer geometry which periodically exhibits ridges, alternatively large (limiting ridges) and thin (intermediate ridges). However, nevus and melanoma lesions differ by the localization of the pigmented stripes along furrows or ridges of the epidermis surface. Here, we propose a biomechanical model of avascular tumour growth which takes into account this specific geometry in the epidermis where both kinds of lesions first appear. Simulations show a periodic distribution of tumour cells inside the lesion, with a global contour stretched out along the ridges. In order to be as close as possible to clinical observations, we also consider the melanin transport by the keratinocytes. Our simulations show that reasonable assumptions on melanocytic cell repartition in the ridges favour the limiting ridges of the basal compared with the intermediate ones in agreement with nevus observations but not really with melanomas. It raises the question of cell aggregation and repartition of melanocytic cells in acral melanomas and requires further biological studies of these cells in situ.
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, Paris 75005, France Faculté de médecine, Institut Universitaire de Cancérologie, Université Pierre et Marie Curie-Paris 6, 91 Boulevard de l'hôpital, Paris 75013, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Balois
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, Paris 75005, France Faculté de médecine, Institut Universitaire de Cancérologie, Université Pierre et Marie Curie-Paris 6, 91 Boulevard de l'hôpital, Paris 75013, France.
authors.forename: Clément
authors.initials: C
authors.lastname: Chatelain
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, Paris 75005, France Faculté de médecine, Institut Universitaire de Cancérologie, Université Pierre et Marie Curie-Paris 6, 91 Boulevard de l'hôpital, Paris 75013, France benamar@lps.ens.fr.
authors.forename: Martine
authors.initials: M
authors.lastname: Ben Amar
mesh_terms: D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D048429:Cell Size; D003198:Computer Simulation; D004817:Epidermis / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000378:metabolism* / Q000473:pathology*; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology*; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology*
chemical_list: D008543:Melanins
keywords: clinical dermatology; geometrical growth and transport; pattern formation; skin cancer morphology; tumour multiphase model