The Role of Melanocyte in Basal Cell Carcinoma

Melanocytes are highly specialized dendritic cells that performs multiple functions through autocrine, paracrine and endocrine mechanisms. These cells are part of a complex system of intercellular communication along with keratinocytes, Langerhans cells and fibroblasts. This intricate network of cellular communication is possible thanks to interaction with cytokines, growth factors and neurotransmitters. Although melanocytes perform brilliantly immunoregulatory and neuroendocrine functions, their fundamental role is to offer protection against the harmful effects of UV radiation through production and transference of melanin to keratinocytes, a process better known as melanogenesis. The latter requires 3 basic proteins to ensure photoprotection: MC1R (activation), MITF (traduction) and TYR (melanin synthesis).

If one of the main features of melanocytes is to avoid UV radiation injurious effect, thus it raises many questions regarding the possible relation between these cells and skin cancer. Currently a great number of melanocytic alterations have been described in melanoma; however in non-melanoma skin cancer the role of melanocytes is less clear. Basal cell carcinoma (BCC) is the most frequent neoplasia worldwide. There are more than 30 histopathologic subtypes, however the nodular subtype is the most common. Pigmented varieties are common in darker skin types, therefore in our country. Previous studies have shown an increase number and size of melanocytes. Melanogenesis were increased at the expense of hyperfunctioning melanocytes as well. In our experience we have noticed the clinical course regarding pigmented nodular basal cell carcinoma is more benign when compared to those without pigment. Most studies regarding the role of melanocytes and pigmentation in basal cell carcinoma have been conducted in caucasian populations, and therefore not representative of what may occur in mestizo population. The aim of the study was to describe the characteristics of melanocytes in pigmented and non-pigmented variants of basal cell carcinoma. Quantify the expression of melanocytic maturation: transcription factors (SOX9 and SOX10), focal adhesion kinase (FAK125) and receptor tyrosine kinase (c-KIT) and melanogenesis such as melanocortin 1 receptor (MC1R), microphthalmia-associated transcription factor (MITF) and tyrosinase (TYR) markers. Investigate the tumoral microenvironment through the quantification of melanin, mast cells, angiogenesis and solar elastosis.