Cutaneous basal cell carcinoma (BCC) is the most common cancer among people of European ancestry (Stacey et al., 2009). The primary environmental risk factor for BCC is sun exposure, but genetics also has a substantial role. Some of the sequence variants that confer susceptibility seem to operate through their association with fair-pigmentation traits common among Europeans, resulting in reduced protection from the damaging effects of ultraviolet (UV) radiation. Other sequence variants have no obvious role in pigmentation or UV susceptibility but instead seem to operate in the contexts of growth and differentiation of the basal layers of the skin (Stacey et al., 2008; Epstein, 2008; Gudbjartsson et al., 2008; Rafnar et al., 2009). See ASIP (600201), TYR (606933), and SHEP5 (227240) for examples of basal cell carcinoma associated with fair skin or sensitivity to sun.
Basal cell carcinoma occurs as a feature of multiple syndromes, including basal cell nevus syndrome (BCNS; 109400), Bazex syndrome (301845), Rombo syndrome (180730), Brooke-Spiegler syndrome (605041), Muir-Torre syndrome (158320), and xeroderma pigmentosum (see 278700).
Abnormalities in the Hedgehog signaling pathway are found in basal cell carcinomas; see SHH (600725) and SMOH (601500).
Genetic Heterogeneity of Susceptibility to Basal Cell Carcinoma
Susceptibility to basal cell carcinoma is a genetically heterogeneous trait. The BCC1 locus maps to chromosome 1p36. Also see BCC2 (613058) on 1q42; BCC3 (613059) on 5p15; BCC4 (613061) on 12q13; BCC5 (613062) on 9p21; and BCC6 (613063) on 7q32. Variation in the 3-prime untranslated region of TP53 (191170) increases susceptibility to basal cell carcinoma (BCC7; 614740).
Somatic mutation contributing to the formation of basal cell carcinoma has been identified in the RASA1 (139150), PTCH1 (601309), and PTCH2 (603673) genes. [from
OMIM]