Skin cancer is a disease in which malignant (cancer) cells form in the tissues of the skin.
The skin is the body's largest organ. It protects against heat, sunlight, injury, and infection. Skin also helps control body temperature and stores water, fat, and vitamin D. The skin has several layers, but the two main layers are the epidermis (upper or outer layer) and the dermis (lower or inner layer).
The epidermis is made up of 3 kinds of cells:
Squamous cells are the thin, flat cells that...
Added text to state that several sets of clinical diagnostic criteria for basal cell nevus syndrome (BCNS) are in use (cited Evans et al. and Veenstra-Knol et al. as references 66 and 68, respectively). Also added text to state that although each set of criteria has advantages and disadvantages, none of the sets have a clearly superior balance of sensitivity and specificity for identifying mutation carriers; PTCH1 mutations are found in 60% to 85% of patients who meet clinical criteria (cited Klein et al. as reference 69).
Added Table 1, Comparison of Diagnostic Criteria for BCNS.
Added text about a 9p22.3 microdeletion syndrome that includes the PTCH1 locus that has been described in ten children, all of whom had facial features of BCNS (cited Muller et al. as reference 109).
Squamous Cell Carcinoma
Added American Cancer Society as reference 1.
Added Doubaj et al. as reference 62.
Added text to state that mutations in C16orf57 are associated with poikiloderma with neutropenia (cited Colombo et al. as reference 151).
Added text to state that mutations in C16orf57 have been identified in individuals with dyskeratosis congenita and poikiloderma with neutropenia, in addition to Rothmund-Thompson syndrome, suggesting that these syndromes are related; however, skin cancer risk in these conditions is not well characterized.
Added text about the Genes, Environment, and Melanoma study, which showed that first-degree relatives of CDKN2A mutation carriers with melanoma had an approximately 50% increased risk of cancers other than melanoma, compared with first-degree relatives of other melanoma patients (cited Mukherjee et al. as reference 88).
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