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Cancer risk factors increase the likelihood of developing cancer, and can be lifestyle-related or genetic. Free notes and 14 questions answered.
Cancer Risk Factors is part of Animal tissues, organs and organ systems in GCSE AQA Higher Biology.
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GCSE AQA Higher
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Cancer risk factors increase the likelihood of developing cancer, and can be lifestyle-related or genetic. Free notes and 14 questions answered.
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Use this lesson to stay inside Animal tissues, organs and organ systems while connecting the detail back to the wider Organisation topic.
Read the core explanations from Cancer Risk Factors before testing yourself from memory.
Cancer isn't random. Scientists have spent decades tracking patterns, asking: why do some people get cancer while others don't? The answer lies in risk factors — things that make cancer more likely to develop.
Think of risk factors like loading dice. Normal cells have built-in protection against becoming cancerous. But each risk factor tips the odds slightly against you. The more risk factors you have, the more loaded the dice become.
Trap: Many students think risk factors guarantee you'll get cancer. They don't. They just increase probability. Someone with multiple risk factors might never develop cancer, while someone with none might still get it.
Lifestyle risk factors are the ones you can control. Scientists have identified several key behaviours that significantly increase cancer risk across different types.
Smoking is the biggest single risk factor. It doesn't just cause lung cancer — it increases risk for at least 14 different cancer types. The chemicals in tobacco smoke are carcinogens that directly damage DNA.
Alcohol consumption increases risk for liver, breast, bowel, and throat cancers. Your liver breaks down alcohol into acetaldehyde, which damages DNA and prevents cells from repairing themselves properly.
Diet and obesity affect cancer risk through multiple pathways. Processed meats contain chemicals that can damage the bowel lining. Excess body fat produces hormones and inflammatory substances that promote cancer growth.
UV radiation exposure from sun or sunbeds damages skin cell DNA directly, leading to melanoma and other skin cancers. The damage accumulates over time — childhood sunburn increases adult cancer risk.
This is where students often get confused about cause and effect. Let's check your understanding:
Some people inherit genetic changes that make them more susceptible to cancer. These aren't lifestyle choices — they're written into your DNA from birth.
The most famous examples are the BRCA1 and BRCA2 gene mutations. Women who inherit these faulty genes have up to an 80% lifetime risk of breast cancer, compared to about 12% for the general population.
Other genetic risk factors include mutations linked to bowel cancer (familial adenomatous polyposis), skin cancer (xeroderma pigmentosum), and various rare cancer syndromes.
Key point: Having a genetic risk factor doesn't mean you'll definitely get cancer. It means your cells are more vulnerable to damage from other factors. This is why genetic counselling often focuses on lifestyle modifications to reduce overall risk.
Risk factors don't work in isolation — they interact. Someone with genetic susceptibility who also smokes faces much higher risk than either factor alone would suggest.
This explains why cancer rates vary so dramatically between populations. Japanese women have lower breast cancer rates than Western women, partly due to different diets and lifestyle factors. But when Japanese women move to Western countries and adopt Western lifestyles, their cancer rates increase.
The interaction works both ways. Protective factors can reduce risk even in genetically susceptible people. Regular exercise, healthy diet, and avoiding carcinogens can significantly lower cancer probability.
Different cancers have different risk factor profiles. Scientists have built this knowledge through decades of epidemiological studies — tracking large populations over time to identify patterns.
Lung cancer: 85% linked to smoking. Other factors include radon gas, asbestos exposure, and air pollution.
Skin cancer: Primarily UV radiation exposure. Fair skin (genetic factor) increases susceptibility.
Breast cancer: Complex mix of genetic factors (BRCA mutations), hormonal factors (age at menopause), and lifestyle factors (alcohol, obesity).
Bowel cancer: Strong links to processed meat consumption, low fibre diet, and inherited genetic syndromes.
Exam questions on cancer risk factors often test your ability to interpret data and evaluate evidence. Here's how to approach them systematically.
Worked example: Worked Example: Applying Cancer Risk Factors
Use this method to answer an exam-style question about what makes cancer more likely?.
Answer: A complete response links mechanism, evidence, and conclusion for cancer risk factors.
Command word focus: 'Explain' questions want you to link the risk factor to the biological mechanism. For example: 'UV radiation damages DNA in skin cells, which can lead to uncontrolled cell division and skin cancer.'
Common mistakes to avoid: Don't confuse correlation with causation. Just because two things happen together doesn't mean one causes the other. Always consider alternative explanations for patterns in data.
Published by Revise Right. Use the official specification reference to check the requirements for your course. Content updated: 2026-03-20.
Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.
A carcinogen is a chemical that can cause cancer by damaging DNA. The chemicals in tobacco smoke are carcinogens that directly damage DNA, which is why smoking increases the risk of at least 14 different cancer types.
About 85% of lung cancer is linked to smoking, the biggest single risk factor, because tobacco smoke contains carcinogens that damage DNA. Other risk factors for lung cancer include radon gas, asbestos exposure and air pollution.
Cancer risk factors are factors that increase the likelihood of developing cancer, and they can be lifestyle-related or genetic. Lifestyle risk factors include smoking, alcohol, diet and obesity, and UV radiation exposure; genetic risk factors include inherited BRCA1 and BRCA2 gene mutations.
Smoking causes cancer because the chemicals in tobacco smoke are carcinogens that directly damage DNA. Smoking is the biggest single risk factor, increasing risk for at least 14 different cancer types, and about 85% of lung cancer is linked to smoking.
A lifestyle risk factor is a behavioural or environmental factor that can be controlled or modified, such as smoking or UV exposure, while a genetic risk factor is inherited from parents and increases susceptibility to disease. A genetic risk factor does not guarantee cancer; it makes cells more vulnerable to damage.
BRCA1 and BRCA2 gene mutations are inherited genetic risk factors for breast cancer. Women who inherit these faulty genes have up to an 80% lifetime risk of breast cancer, compared to about 12% for the general population.
Having a risk factor does not guarantee cancer; risk factors only increase the probability of developing it. Someone with multiple risk factors might never develop cancer, while someone with none might still get it, and risk factors interact, so a genetically susceptible smoker faces much higher risk.
Alcohol increases cancer risk because the liver breaks alcohol down into acetaldehyde, which damages DNA and prevents cells from repairing themselves properly. Alcohol consumption increases the risk of liver, breast, bowel and throat cancers.
Obesity increases cancer risk because excess body fat produces hormones and inflammatory substances that promote cancer growth. Diet also plays a part, since processed meats contain chemicals that can damage the bowel lining.
Breast cancer has a complex mix of risk factors: genetic factors such as BRCA mutations, hormonal factors such as age at menopause, and lifestyle factors such as alcohol and obesity. Women with faulty BRCA genes have up to an 80% lifetime risk, compared to about 12% generally.
Bowel cancer has strong links to processed meat consumption, a low fibre diet and inherited genetic syndromes such as familial adenomatous polyposis. Alcohol consumption also increases bowel cancer risk.
Cancer risk factors interact rather than working in isolation. Someone with genetic susceptibility who also smokes faces much higher risk than either factor alone would suggest, while protective factors such as regular exercise, a healthy diet and avoiding carcinogens can lower risk even in genetically susceptible people.
Japanese women have lower breast cancer rates than Western women, partly due to different diets and lifestyle factors. When Japanese women move to Western countries and adopt Western lifestyles, their cancer rates increase, showing that lifestyle risk factors matter.
Scientists find cancer risk factors through epidemiological studies, tracking large populations over time to identify patterns. Different cancers have different risk factor profiles, but correlation is not the same as causation, so alternative explanations for patterns in data must be considered.