Causes Of Cancer Essay Example | Topics and Well Written Essays - 1000 words

Causes Of Cancer - Essay Example Occupation-related cancer comprises 5 to 20% of the cases. The minimum of 200,000 people worldwide dies annually from cancer induced by harmful workplace conditions. The majority of deaths linked to occupational risk factors happen in the developed countries. In the U.S. only, 20,000 cancer deaths and 40,000 newly registered cases a year can be attributed to dangerous chemicals inhaled or contacted with while at work. Genetic factors can also play a crucial role in cancer development. Mutations of the genome alter the growth patterns and make targeted cells potentially cancerous. Sometimes, genetic mutations may be present from the moment of birth, and a syndrome is called family cancer syndrome. The mutation usually occurs in one or several tumor suppressor genes. Such individuals are predisposed to having cancer, but they do not necessarily develop clinical signs. Every gene is represented in the cell with two copies called alleles. Cancer syndromes are usually transferred in the autosomal dominant way. This means that even one altered allele is enough for the individual to be predisposed to cancer. Potential children of such a person and an individual with two intact alleles are at a 50% risk of being born sick (Brown & Anderson, 2007). The regularity, called a two-hit hypothesis, says that the first hit is the genome mutation and the second one happens later in life. Since only one allele is to be altered, the chance of developing a disease is higher in affected people than in the rest of population.