PATHOLOGY

Detailed explanation-1: -A DNA change can cause genes involved in normal cell growth to become oncogenes. Unlike normal genes, oncogenes cannot be turned off, so they cause uncontrolled cell growth.

Detailed explanation-2: -Cancer is unchecked cell growth. Mutations in genes can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death. As a mass of cancerous cells grows, it can develop into a tumor.

Detailed explanation-3: -Usually, cells die when they get too old or damaged. Then, new cells take their place. Cancer begins when genetic changes interfere with this orderly process. Cells start to grow uncontrollably. These cells may form a mass called a tumor.

Detailed explanation-4: -Cancer cells have gene mutations that turn the cell from a normal cell into a cancer cell. These gene mutations may be inherited, develop over time as we get older and genes wear out, or develop if we are around something that damages our genes, like cigarette smoke, alcohol or ultraviolet (UV) radiation from the sun.