Causes of Melanoma

Melanocytic tumors can be composed of epidermal melanocytes, nevus cells or dermal melanocytes. The tumor originates from the neural crest of the ectoderm. Melanocytes are located between the epidermis and basal cells. After the cells produce pigments, they transport melanin particles to basal cells and hair through dendrites. The true cause of normal melanocyte tumors is still unclear, and may be related to the following factors:

1. Benign melanin plaques are moles, among which junctional moles are most likely to become malignant, mixed moles are less likely, and endothelial moles rarely become malignant. However, most scalp melanomas are not transformed from moles, so some people believe that this disease is not entirely related to moles.

2. Sunlight and ultraviolet radiation. Melanoma of the scalp is more common in exposed parts. According to Israeli statistics, the annual incidence rate of agricultural workers is 15.4/100,000, which is higher than that of urban workers. The incidence rate of residents living in coastal areas is higher than that of those living in mountainous areas. Since the 1980s, the incidence rate of melanoma has more than doubled, which is estimated to be related to the destruction of the atmospheric ozone layer and excessive exposure of the skin to ultraviolet rays.

3. The incidence rate among white people is higher than that among people of color. For example, the annual incidence rate among white people in the United States is as high as 42/100,000, while that among black people is only 0.8/100,000.

4. Other factors such as genetics, trauma, chronic mechanical stimulation, etc. may also be pathogenic factors.