1. Melanoma is a cancerous factor that has attracted much attention in the past two years.
2. There are many pigments in Chinese skin, which have a good protective effect against ultraviolet rays.
3. At the same time, we also pay more attention to sunscreen in daily life, so malignant melanoma is relatively rare in China.
4. Because melanoma is black, it is easy to find, so if black spots are found in nails, nail beds, soles of feet, palms or other parts of the body.

Moreover, it has significantly expanded in the near future, and it is easy to break, or half of the nail is blackened. We should be alert and go to the hospital for examination in time.

5. Squamous cell carcinoma is often transformed from keratosis, mucosal leukoplakia and other precancerous diseases.
It grows faster and forms ulcers in the early stage. Some are nodular or cauliflower shaped, with less invasion to the deep, and the base can be moved; Some are butterfly shaped, with obvious infiltration to the deep, destructive, and often involving bones.
Squamous cell carcinoma is often accompanied by suppurative infection, odor and pain.
6. Basal cell carcinoma is often asymptomatic at the onset. At the initial stage, it is mostly plaque papules on the base, and some are verrucous.

Then it breaks and changes into ulcer foci, irregular, with uplifted edges, like a crater, uneven bottom and slow growth.

Metastasis is rare. At first, there is a translucent nodule on the edge, which bulges shallow in the ulcer, and then gradually expands, which can erode the surrounding tissues and organs and become an erosive ulcer.