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.
Agents that may cause cancer include: Chemical carcinogens. Several chemicals and environmental toxins are responsible for changes in normal cellular DNA. Substances that cause DNA mutations are known as mutagens, and mutagens that cause cancers are known as carcinogens. Particular substances have been linked to specific types of cancer. Tobacco smoking is associated with many forms of cancer, and causes 90% of lung cancer.