If melanocytes in nevus are frequently stimulated, the number of abnormal cell division, proliferation and repair will increase. This process may induce oncogene mutation and increase the risk of malignant transformation. Most people have some moles on their bodies or faces. Some moles are safe with people all their lives, but some moles are "dangerous elements", and unconsciously grow into cancer - malignant melanoma. Although the incidence rate of malignant melanoma is not high, it has high malignancy, early metastasis and high mortality. Recently, at the first Jiangsu sarcomas and malignant melanoma conference held in Nanjing, some experts reminded that nevus growing in the vulnerable parts should be treated as soon as possible; The whiter the skin, the more attention should be paid to avoid exposure to the sun. Song Dan, chairman of sarcoma and malignant melanoma Professional Committee of Jiangsu Provincial anti cancer association and chief physician of Radiotherapy Department of Jiangsu Provincial Cancer Hospital, said that there are about 20000 new cases of malignant melanoma in China every year, but it has increased rapidly in recent years. In the past 50 years, the incidence rate has increased about 6 times. Soft tissue sarcoma also has a similar situation. Clinically, about 35% - 50% of melanomas occurring in the trunk or limbs are related to primary nevus and also closely related to repeated short wave ultraviolet irradiation. This also makes many people worry that their moles will secretly grow into cancer? "There are actually quite a few cases of nevus to cancer." Song Dan said. "If the nevus grows in a place that is easy to be rubbed, such as the waist, the sole of the foot, the back, etc., it should be treated as soon as possible. If the nevus is stimulated by needle picking, corrosive drugs or incomplete freezing and laser, it may cause the nevus to become malignant." Song Dan explained that if melanocytes in nevus are frequently stimulated by undesirable stimuli, they will increase the number of abnormal cell division, proliferation and repair. This process may induce oncogene mutations and increase the risk of malignant transformation. "If you need to remove the nevus because of beauty, you should go to the specialized outpatient department of a regular hospital, and professional doctors should evaluate the removal method. You can't remove the nevus at will to avoid improper stimulation and carcinogenesis." Song Dan suggested. The whiter your skin, the more you should avoid exposure to the sun. "Excessive ultraviolet radiation will induce malignant melanoma." is there any scientific basis for these voices in the network "people with fair skin are more likely to get malignant melanoma when exposed to the sun"? Song Dan said that the relationship between exposure to sunlight and malignant melanoma needs to be analyzed in terms of race and specific conditions. Song Dan introduced that European and American people belong to white people, and the incidence rate of malignant melanoma is higher than that of other races. The types of malignant melanoma in European and American populations are mainly superficial diffuse type and freckle nevus type, which are closely related to the sun; In contrast, the Chinese and other Asian people suffer from more acral and mucosal malignant melanomas. These melanomas grow deep and are easy to metastasize. They are not particularly related to exposure to the sun, but the impact of ultraviolet rays cannot be completely ignored. "This is because the whiter the skin, the less melanin the skin contains, and the weaker the protection against ultraviolet rays. If you are exposed to improper sunlight, such as frequent sunbathing, frequent sunburn, or frequent 'tanning' by ultraviolet light irradiation, you may be at risk of inducing malignant melanoma." Song Dan reminds me that sunbathing can supplement