Identification of risk factors and estimation of individual risk for malignant melanoma is an important task for clinicians, and grading populations according to risk of disease facilitates clinical work and can determine strategies for primary prevention and guide different levels of screening. High-risk groups should be recruited into prevention trials. The following multiple factors are risk factors for malignant melanoma: 1. Skin type: The incidence of malignant melanoma in Caucasians is more than 10 times that of African Americans and 7 times that of Hispanic Americans. Those with fair skin or red hair, light skin and blue eyes have a greater risk of malignant melanoma. 2. Age: The incidence of malignant melanoma increases with age. Some data show that there is no difference in the incidence of malignant melanoma between men and women below the age of 50, while it is more common in men above the age of 50. 3. Gender: Malignant melanoma tends to be more common in men. Specifically, a man’s risk of developing malignant melanoma during his lifetime is 1.7 times higher than that of a woman. 4. Tanning bed use: For people over 30 years of age, the risk of malignant melanoma is doubled for those who use tanning beds more than 10 times in a year. For those under that age who used tanning beds more than 10 times in a year, the risk was 7 times higher than that of non-users. 5, previous history of malignant melanoma: the likelihood of secondary malignant melanoma in patients with previous malignant melanoma is 3% to 7%, and the risk is 900 times higher than that of the normal population. Sun exposure: Occasional or recreational exposure to sunlight increases the risk of developing malignant melanoma, especially in those with a history of severe sunburn. The number of severe and painful sunburns correlates with the risk of malignant melanoma, with a history of 10 or more severe sunburns increasing the risk of malignant melanoma by a factor of 1 compared to those with no history of sunburns. It is also important to note that sun exposure in people over 20 years of age also increases the risk of developing malignant melanoma. Ultraviolet light from sunlight is the culprit, and approximately 2/3 of malignant melanomas are caused by UV radiation according to the presumed mechanism that can cause malignant melanoma. 7. Benign moles: Although most moles do not develop into malignant melanoma, the presence of multiple moles indicates an increased risk of malignant melanoma. Those with 50 or more moles, all of which are larger than 2 mm, have 5 to 17 times the risk of developing malignant melanoma than those with fewer moles. Family history: Family history of malignant melanoma increases the risk of malignant melanoma by 3 to 8 times, and the risk of malignant melanoma is higher if two or more people in the family have malignant melanoma. 9. Genetic susceptibility: Alterations in specific genes may lead to the development of malignant melanoma. At least four mutually independent genes play a role in the development of malignant melanoma: chromosomes 1p, 6q, 7 and 9. The tumor suppressor gene located at 9p21 is associated with familial and disseminated cutaneous malignant melanoma, and deletions or rearrangements of chromosomes 10 and 11 may also cause the development of cutaneous malignant melanoma. Recent genetic studies have demonstrated that specific genetic changes can lead to susceptibility to cutaneous malignant melanoma. For example, patients with variants outside the coding region of CDKN2A are susceptible to malignant melanoma because variants at the 5′ end of the CDKN2A gene create a new upstream promoter that prevents the expression of the p16 gene, which is a necessary step for tumor suppression. Another genetic change that may play a role in tumorigenesis is a mutation in the B-RAF gene, a member of the serine/threonine-specific protein kinase family, which is part of a signaling pathway that is integral to cell proliferation, differentiation and survival. In mammals, there are three isoforms of this gene: A-RAF, B-RAF and C-RAF. Recently, mutations in the B-RAF isoform have been found to be present in a high proportion of patients with malignant melanoma (about 60%-70%), with most of the mutations being due to environmental factors and manifesting as deletions or rearrangements. The findings of most studies suggest that B-RAF is not a genetic susceptibility gene for malignant melanoma, and some investigators prefer to hypothesize that this gene plays a key role in stopping disease progression in the early stages of malignant melanoma. Mutations in glutamate instead of valine at V600E account for 90% of B-RAF mutations in malignant melanoma. This mutation causes activation of the downstream mitochondria-activated protein kinase signaling pathway and causes progression of malignant melanoma by an as yet unknown mechanism. 10. Atypical birthmark and melanoma syndrome: once named abnormal developmental nevus syndrome. Atypical birthmark and melanoma syndrome is an independent pathophysiological type of melanoma cell lesion manifested by a large number of atypical birthmarks (abnormal developmental nevi). It can develop into malignant melanoma and is also a high risk factor for malignant melanoma. Although atypical birthmarks are statistically less likely to develop into malignant melanoma, patients with atypical birthmarks and melanoma syndrome should be closely monitored and their family members should be monitored as well.