Cancer is a group of diseases consisting of abnormal cell development with the potential to invade or spread to other parts of the body. They form a subset of neoplasms. A neoplasm or tumour is a group of cells that have undergone unregulated growth and will often form a mass or lump, but may be distributed diffusely. Lung cancer is a condition that causes cells to divide in the lungs uncontrollably. This causes the growth of tumors that reduce a person's ability to breathe. Typically, the body programs cells to die at a certain stage in their life cycle to avoid overgrowth. Cancer overrides this instruction, causing cells to grow and multiply when they should not. The overgrowth of cells leads to the development of tumors and the harmful effects of cancer. In lung cancer, this pattern of cell overgrowth occurs in the lungs, which are vital organs for breathing and gas exchange.
