Genetics of Skin Cancer (PDQ®): Genetics - Health Professional Information [NCI] - Squamous Cell Carcinoma
Table 3. Hereditary Syndromes Associated with Squamous Cell Carcinoma of the Skin continued...
Some evidence suggests nonallelic heterogeneity in epidermodysplasia verruciformis. An individual born to consanguineous parents with epidermodysplasia verruciformis and additional bacterial and fungal infections was found to have homozygous R115X mutations in the MST1 gene. Another susceptibility locus associated with this disorder has been identified at chromosome regions 2p21-p24 through linkage analysis of an affected consanguineous family. Unlike those with mutations in the EVER1 and EVER2 genes, affected individuals linked to this genomic region were infected with HPV 20 rather than the usual HPV subtypes associated with this disorder, and this family did not have a history of cutaneous SCC.
Fanconi anemia is a complex disorder that is characterized by increased incidence of hematologic and solid tumors, including SCC of the skin. Fanconi anemia is inherited as an autosomal recessive disease. It is a relatively rare syndrome with an estimated carrier frequency of one in 181 individuals in the United States (range: 1 in 156 to 1 in 209) and a carrier frequency of up to one in 100 individuals of Ashkenazi Jewish ancestry. Leukemia is the most commonly reported cancer in this population, but increased rates of gastrointestinal, head and neck, and gynecologic cancers have also been seen. By age 40 years, individuals affected with Fanconi anemia have an 8% risk per year of developing a solid tumor; the median age of diagnosis for solid tumors is 26 years. Multiple cases of cancers of the brain, breast, lung, and kidney (Wilms tumor) have been reported in this population. Data on the incidence of nonmelanoma skin cancers in this population are sparse; however, review of the literature suggests that the age of diagnosis is between the mid-20s and early 30s and that women seem to be affected more often than men.[139,140,141,142,143]
Individuals with this disease have increased susceptibility to DNA cross-linking agents (e.g., mitomycin-C or diepoxybutane) and ionizing and UV radiation. Cells from individuals with Fanconi anemia have shown decreased ability to excise pyrimidine dimers. The diagnosis of this disease is made by observing increased chromosomal breakage, rearrangements, or exchanges in cells after exposure to carcinogens such as diepoxybutane.
Thirteen complementation groups have been identified for Fanconi anemia; details regarding the genes associated with these groups are listed in Table 4 below.