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Asked by anon-72819 to Barbara, Matt, Ravinder, Sophie, Tristan on 10 Mar 2015.
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Sophie Robinson answered on 10 Mar 2015:
Cancer affects some people and not others because it is caused by mutations happening within cells of the body when they divide. Mutations occur naturally when our cells divide and copy their DNA. Mistakes are made randomly during this process and sometimes are not repaired. This is why the incidence of cancer increases with age: because the tissues of older people have undergone many more cell divisions than younger people. However, mutations are also caused by exposure to environmental factors such as tobacco, UV light and certain chemicals. Additionally, some people are born with certain mutations that they have inherited from their parents.
Therefore, some people are exposed to more environmental factors that increase their chance of cancer and some people are essentially just ‘unlucky’ that mutations occurred at the wrong place and wrong time.
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Matthew Moore answered on 10 Mar 2015:
Because there are about 100 different types of cancer, so it depends on where in the body it is, whether it gets a blood supply, travels to different parts of the body and when it’s discovered! Tumours are highly variable and the state of someones body is going to be a factor in how likely they are to survive it!
If somebody is already ill for example, then it will be worse for them.
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Barbara Shih answered on 10 Mar 2015:
There are many different types of cancers, and different gene changes are involved the cancers of different individuals. If it’s cancers of the same type, some patients’ cancers may have more “difficult” mutations – such as mutations that make them very slippery (so they travel around the body more), mutations that make them invisible to immune cells, or mutations that make the cancer resistant to drug treatments.
There are also differences in people’s genetics makeup. Some people might have genes that allow their immune cells to have a better chance of noticing cancerous cells. Some people have genes that are normally fine, but have these tiny changes (mutations or polymorphisms) that normally don’t cause any harm, but have a slightly higher chance of turning cancerous. For example, individuals with inherited mutations in BRAC1 are more likely to get breast cancer. BRAC1 is involved in DNA repair/response to DNA damage. A more extreme example would be people who have Xeroderma pigmentosum; these individuals have defect DNA repair against damage caused by UV, and if they did not use a lot of sunscreen, half of the children would develop skin cancer by the age of 10.
Other important factors are as Sophie and Matt already mentioned.
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