Cancer is caused by genetic changes leading to uncontrolled cell growth and tumor formation. The basic cause of sporadic (non-familial) cancers is DNA damage [citation needed] and genomic instability. [1] A minority of cancers are due to inherited genetic mutations. [2] Most cancers are related to environmental, lifestyle, or behavioral the development of cancer, for example, smoking has been proven to be a definitive cause of lung cancer. However, it is often not so simple; some carcinogens are associated with some cancers and not others, as is the case for radiation and benzene, which are risk factors for certain types of leukemia, but not for colon cancer6 7. As a result of In 2014, cancer research represents over 4 % of all re- search performed globally, reflecting the huge amount of effort that has been invested worldwide to address this multifaceted and complex disease. Today it is the leading cause of premature death in 28 European countries1 and across the United States (US)2. Pollution of the air (indoor and outdoor), water, and soil causes an estimated 1 to 4 percent of all cancers worldwide ( Stewart and Kleihues, 2003 ). Even though the risk levels per person are quite low, the large numbers of people exposed—involuntarily—can mean a substantial population effect. ¥A somatic mutation causes a sporadic cancer. 8 Properties of Cancer Cells: Autocrine stimulation, Lack of contact inhibition, Lack of cell death, Lack of gap junctions. 9 Properties of Cancer Cells: Lack of contact inhibition Normal skin cells Grow in monolayer Skin cancer cells Do not grow in monolayer Pile up on each other. 10 Human Cancer: Known Causes and Prevention by Organ Site IARC Monographs on the Identification of Carcinogenic Hazards to Humans and Handbooks of Cancer Prevention. Interventions with sufficient evidence of a cancer-preventive effect (in green) Group 1 agents with less than . sufficient. evidence in humans. There may be no signs or symptoms at all in the early stages of cervical cancer. The presence of cancer may be indicated by vaginal bleeding, contact bleeding (of which the most frequent type is bleeding after sexual contact), or (rarely) a vaginal area. Additionally, vaginal discharge and mild pain during sex are signs of cervical cancer. Various kinds of organisms, including viruses, bacteria, trematodes and fungi are known carcino- gens that cause cancer. Infectious identification related to cancer may lead to better treatment for both the prevention and targeting of cancer therapy. Evidence that the various common types of cancer are largely avoidable diseases is reviewed, and it is suggested that, apart from cancer of the respiratory tract, the types of cancers that are currently common are not peculiarly modern diseases and are likely to depend chiefly on some long-established factor. Evidence that the various common types of cancer are largely avoidable diseases is Cause of the cancer differs across groups, causes cancer at different ages Subtypes can be caused by different factors -can contribute to disparities Timing or intensity of exposure For example, exposure to tobacco could occur earlier in one population Timing, prevalence and frequency of early cancer detection Cells become cancerous due to the accumulation of defects, or mutations, in their DNA. Certain: inherited genetic defects (for example, BRCA1 and BRCA2 mutations), infections, environmental factors (for example, air pollution), and poor lifestyle choices -- su