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.
Cancer is caused by changes (mutations) to the DNA within cells. The DNA inside a cell is packaged into a large number of individual genes, each of which contains a set of instructions telling the cell what functions to perform, as well as how to grow and divide. Normal cells know when to stop growing so that you have just the right number of each type of cell. 2  Cancer cells lose the controls (tumor suppressor genes) that tell them when to stop growing. 3  A mutation in a tumor suppressor gene allows cancer cells to continue growing and accumulating.