There are many causes of nevus cancer, so we should pay attention to the changes of nevus in our life, and once we find any abnormal phenomenon, we should have timely treatment, and we should also have some understanding of the types of nevus cancer. 1.Asymmetrical nevus cancer is very harmful to our body, so we must pay attention to our nevus actively in life, and seek medical treatment when one half of the pigmented nevus looks asymmetrical to the other half. 2. Irregular edges The edges of nevi are irregular or have cut marks or jagged teeth, unlike normal pigmented nevi that have smooth round or oval outlines. 3.Color change Normal pigmented nevus is usually monochromatic, while melanoma mainly shows dirty black, and can also have many different colors such as brown, brown, brown-black, pink, blue, black or even white. 4. Diameter It is important to pay attention when the diameter of pigmented spots is larger than 5-6mm or when the pigmented spots grow up. Generally, melanoma is usually larger than ordinary moles, and we remind you that you must pay attention to pigmented moles with diameter larger than 5mm. This type of mole is very prone to nevus cancer. Some early melanomas will have a slight elevation of the whole tumor some early melanomas will have a slight elevation of the whole tumor. 6.Growth speed Once some pigmented nevi that have not changed for years increase significantly within a few weeks or months, you must pay attention to the cancerous nevi. 7.Pigmented nevus abnormalities Sudden loss of hair on pigmented nevus, or breakage that does not heal easily, may lead to nevus cancer.