The dermis, the skin's next layer, is a thick layer of fibrous and elastic tissue (made mostly of collagen, with a small but important component of elastin) that gives the skin its flexibility and strength. The dermis contains nerve endings, sweat glands and oil (sebaceous) glands, hair follicles, and blood vessels.
âAll cancers are caused by genetic mutations, and in some cases we know the processes driving them, for example, tobacco smoking in lung cancer, however, our understanding of the causes of mutation in most cancers is remarkably limited,â Grimmond says.
Genetic risk factors. About 5% to 10% of breast cancer cases are thought to be hereditary, meaning that they result directly from gene defects (called mutations) inherited from a parent. BRCA1 and BRCA2: The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 and BRCA2 genes. People with this syndrome have an increased risk of breast cancer, as well as several other cancers such as leukemia, brain tumors, and sarcomas (cancers of bones or connective tissue). 2  This is a rare cause of breast cancer. 3  CHEK2: The Li-Fraumeni syndrome can also be caused by inherited mutations in the CHEK2 gene.