There are melanocytes in every human body, which are evenly distributed in our skin. If they over-divide and proliferate and gather into clusters, they become dark pigmented nevi, which are often called ‘nevi’, and when such division and abnormal proliferation are out of control, they evolve into malignant melanoma. The incidence rate of melanoma is high abroad, but the incidence rate of malignant melanoma in China is not high, about 0.4-0.5 per 100,000, however, from the general trend, the incidence rate of malignant melanoma has been increasing in recent years all over the world. If an existing mole becomes painful, itchy, or ulcerated, this is a red flag that the mole has changed malignantly. Melanoma is common in the palms of the hands, feet, skin mucous membrane, mouth and other parts of the body, which often suffer from friction and are prone to malignant changes, so it is recommended that moles growing in these parts should be treated early. Melanoma has more causative factors, but the most recognized one is excessive sun exposure. The melanocytes in Caucasian skin are more sensitive to excessive sunlight, which is why they are more likely to develop in Caucasians. The cause of melanoma formation in Caucasians is unknown and is thought to be related to genetic mutations. After the age of 30, new moles over 0.6 CM should be beware of Many moles can be found in various parts of the body, generally more on the face and neck. Common freckles, pigmented spots and intradermal nevi are benign and have no tendency to become malignant, so they generally do not require treatment. Junctional nevi (generally smooth or slightly above the surface, usually without hair growth, with color ranging from light brown, brown, greenish gray to blue, usually found on the palm of the foot, palm of the hand, genitalia and vulva) have a malignant tendency, and if the surrounding area is broken, painful or bleeding is felt, or other small nevi (satellite foci) begin to grow around them, it indicates the possibility of malignant transformation. If the nevus grows on the palm of the hand or foot, it should be removed early. Mixed nevus is a mixture of intradermal nevus and junctional nevus, most of which are not higher than the surface, round or oval in shape, and irregular in size, making clinical diagnosis more difficult. Blue nevus often grows on the buttocks, dorsum of the feet, dorsum of the hands and face, and the pigmentation ranges from brown to blue. New moles over 0.6CM after the age of 30 should be taken seriously enough to be diagnosed at a dermatology clinic. A mole that has been stable on the body before the age of 30 but has recently grown rapidly suggests the possibility of malignant transformation. Benign moles usually have regular and clear borders, so be alert when moles with blurred borders appear. Darkening or lightening of the color of a mole is also a sign of instability. It is also important to pay attention when a mole appears to be itchy and painful from time to time and ulcerates for no reason. When redness or small black spots appear around the original mole, it may be an early sign of malignant change. Can melanoma be cured in the early stage? Although malignant melanoma has a high mortality rate, it is not “impossible for anyone”. At present, melanoma is not sensitive to traditional tumor treatments such as radiotherapy and chemotherapy. However, from nevus to melanoma, melanocytes have a time process to proliferate on the skin, and it is possible to cure melanoma through treatment in the early stage. With surgical excision and cellular immunotherapy methods, patients can have a five-year survival rate of 30%. Early complete excision of melanoma is sent for pathological examination, and then expanded excision and adjuvant therapy can be performed after the diagnosis is confirmed according to the pathology, which can achieve better treatment results. However, if treatment is abandoned or delayed and melanin is allowed to proliferate, once melanoma cells invade the blood vessels and lymphatic vessels in the skin dermis, they will easily metastasize to various organs throughout the body and eventually die.