Melanocyte Pygmentation – Friend or Foe on the Route to Melanoma

摘要: The epidermis forms the top protective covering of normal human skin and is itself composed multiple layers from stratum corneum at top, to proliferating cells in deep/basal layer (Liu & Fisher, 2010). epidermal cell population mainly constituted two types: keratinocytes melanocytes. Keratinocytes constitute majority epidermis; they have a “supporting” regulatory role for are linked through tight desmosomal intercellular junctions also anchored into basal membrane hemidesmosomes, but melanocytes remain as singly scattered, unattached cells. Each single, well-differentiated, melanocyte interacts with 36 viable various stages progression upper cornified (Fitzpatrick Breathnach, 1963) form units. These structural functional cellular units exhibit complex, life-long, interactions originally laid down during embryonic life. There considerable interindividual intraindividual variations densities, more than twice many located head forearm compared elsewhere on body, well darker folded areas axillae perineum, traits that remarkably consistent between races (Szabo, 1967). Despite significant variation pigmentation, density epidermal-dermal junction very similar across different types (Yamaguchi Hearing, 2009). Thus main contributor racial differences pigmentation activity rather absolute numbers Melanocytes play central response sunlight exposure. They directly involved UV-induced defense mechanism. People color possess varied sensitivity ultraviolet (UV) exposure, skinned individuals being less susceptible sun-induced alterations, including cancer, fair ones (Elwood Diffey 1993). Such difference can be explained terms UV filtering by because related type melanin, number, size, type, distribution degradation melanosomes, tyrosinase (Nordlund Ortonne 1998, Yamaguchi Hearing decreased photocarcinogenesis seen may attributed efficient removal UV-damaged 2009, Alonso Fuchs, 2003, 2008).