A gene that makes a protein called KRAS, which is involved in cell signaling pathways that control cell growth, cell maturation, and cell death. The natural, unchanged form of the gene is called wild-type KRAS. Mutated (changed) forms of the KRAS gene have been found in some types of cancer, including non-small cell lung cancer (NSCLC), colorectal cancer, and pancreatic cancer. These changes may cause cancer cells to grow and spread in the body. Knowing whether a patient’s tumor has a wild-type or mutated KRAS gene may help plan cancer treatment. Also called K-RAS gene.