<Tr> <Th> Deaths </Th> <Td> 8.8 million (2015) </Td> </Tr> <Tr> <Td_colspan="2"> (edit on Wikidata) </Td> </Tr> <P> Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body . These contrast with benign tumors, which do not spread to other parts of the body . Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements . While these symptoms may indicate cancer, they may have other causes . Over 100 types of cancers affect humans . </P> <P> Tobacco use is the cause of about 22% of cancer deaths . Another 10% are due to obesity, poor diet, lack of physical activity, and excessive drinking of alcohol . Other factors include certain infections, exposure to ionizing radiation and environmental pollutants . In the developing world nearly 20% of cancers are due to infections such as hepatitis B, hepatitis C and human papillomavirus infection . These factors act, at least partly, by changing the genes of a cell . Typically many genetic changes are required before cancer develops . Approximately 5--10% of cancers are due to inherited genetic defects from a person's parents . Cancer can be detected by certain signs and symptoms or screening tests . It is then typically further investigated by medical imaging and confirmed by biopsy . </P>

Cancer is a disease that usually results when