1. Causes of Cancer

2. Ageing Most types of cancer become more common as people age
Older people have had more time for their DNA to mutate as a result of carcinogens
Different mutations to DNA have to occur for cancer to develop
It can take years for several mutations to occur

3. Heredity
There need to be a lots of genetic mutations within a cell before it becomes cancerous.
If a person is born with one of these mutations it doesn't mean they will definitely get cancer.
BRCA1 and BRCA2 can mutate to cause breast cancer
60% lifetime risk of developing breast cancer
Higher risk of developing ovarian cancer

4. Viruses Viruses can cause some types of cancer
The virus can cause genetic changes in cells that make them more likely to become cancerous.
Most cervical cancer cases are caused by the Human Papilloma Virus

5. Chemical Carcinogens Arsenic = lung and skin cancer
Drinking contaminated water
Eating contaminated food
irrigation of food crops
industrial processes.
Hair dye = Bladder Cancer
In 2008, the World Health Organisation (WHO) that they can increase the risk of bladder cancer for male hairdressers and barbers because they are working with the chemicals all the time.
Alcohol = oesophageal (more common in men) and oropharyngeal cancer (throat,speaking and swallowing)

6. Evaluating Epidemiological Evidence
EPIC - a study that collects a lot of data
-Data is assessed
-Correlation is analysed (Factor vs increase risk of cancer)
-In correlation is ‘strong positive’ then the government are inform
-The results are then published
An EPIC was conduction on tobacco smoke and the results had such a strong positive correlation with relationship to lung cancer that governments across Europe to introduce a ban on smoking in public places
Epidemiology is the study (or the science of the study) of the patterns, causes, and effects of health and disease conditions in defined populations.

7. Case Study: Processed Meat
Bowel cancer risk was a third higher in those who ate two 80g portions of processed meat a day.
Red meat includes lamb, pork, ham, bacon, sausages, liver plate, salami and tinned meat.
Red meat that is preserved by methods other than freezing can increase the risk of bowel cancer.
No theory has been conclusively linked to causing cancer, there are several ideas among scientists about the health risks associated with processed (red) meat.

8. Though no theory has been conclusively linked to causing cancer, there are several ideas among scientists about the health risks associated with processed (red) meat.
One theory is that haemoglobin and myoglobin, two polypeptides found in red meat, trigger a process called nitrosation in the gut, which can lead the formation of carcinogens.
Alternatively, scientists believe a particular group of chemicals (heterocyclic amines), which are formed in the cooking process can increase the risk of cancer.