Cancer — AQA GCSE Combined Science
Test yourself on Cancer with AQA GCSE practice questions.
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Cancer explained
Cancer begins when changes in a cell's genetic material alter the control of the cell cycle.
Read the full explanation
Normally, cell division is regulated so that new cells are produced only when needed for growth or repair. After these changes, the cell divides repeatedly without responding to the usual controls, producing an uncontrolled growth and division that forms a mass of abnormal cells called a tumour. Tumours that invade neighbouring tissues and spread to other parts of the body through the blood or lymph are malignant and are described as cancer. Benign tumours grow in one place and do not invade or spread. Risk factors such as smoking, obesity, ultraviolet radiation and some viruses increase the chance of the cell changes occurring, but they do not guarantee that cancer will develop.
Benign tumours are growths of abnormal cells which are contained in one area, usually within a membrane. They do not invade other parts of the body.
A benign tumour is a localised growth of abnormal cells. Cell division has gone wrong, so cells multiply when they should not, but the mass stays in one place. It is usually enclosed by a membrane, which helps keep it contained. Because it does not invade neighbouring tissues, it cannot travel in the blood to start new growths elsewhere. A common example is a mole or a fatty lump under the skin; these are usually harmless, though a benign tumour in the brain can still cause problems by pressing on tissue. Students should link this to uncontrolled cell division and contrast it with malignant tumours, which do invade and spread. The key idea is containment: one area, usually a membrane, no invasion.
Malignant tumour cells are cancers. They invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours.
A malignant tumour is a cancer. Its cells divide uncontrollably and do not stay contained. They invade neighbouring tissues, breaking into them and damaging their normal function. Malignant cells can also enter the blood or lymphatic system and travel to other parts of the body. Where they settle, they divide again to form secondary tumours, often called metastases. This spread is why cancers can affect organs far from where they started. For example, a malignant tumour in the lung can release cells that travel in the blood and form a secondary tumour in the liver or brain. Students should link invasion and spread to the blood as the key features that make a tumour malignant.
Scientists have identified lifestyle risk factors for various types of cancer. There are also genetic risk factors for some cancers.
Cancer begins when changes in DNA cause cells to divide uncontrollably, forming a tumour. Scientists have identified lifestyle risk factors that increase the chance of these changes, such as smoking tobacco, drinking alcohol, obesity, poor diet, lack of exercise, and overexposure to ultraviolet radiation. These factors are avoidable or reducible, so they affect incidence at population level. Genetic risk factors are inherited alleles that raise susceptibility to particular cancers, for example BRCA variants linked to breast and ovarian cancer. A person may inherit a risk and still never develop cancer, because risk is probabilistic, not certain. Reducing lifestyle risks lowers, but does not remove, the chance of cancer.
Your focus
- Describe cancer as the result of changes in cells that lead to uncontrolled growth and division.
- Explain how uncontrolled division produces a tumour and distinguish malignant from benign tumours.
- Relate named risk factors to an increased chance of the cell changes that lead to cancer.
Show all 12 objectives
- Describe a benign tumour as a growth of abnormal cells contained in one area, usually within a membrane.
- Explain that benign tumours do not invade other parts of the body.
- Compare benign tumours with malignant tumours in terms of invasion and spread.
- Describe malignant tumour cells as cancers that invade neighbouring tissues.
- Explain how malignant cells spread in the blood to form secondary tumours in other parts of the body.
- Distinguish malignant tumours from benign tumours by their invasion and spread.
- State that cancer involves uncontrolled cell division and tumour formation.
- Identify named lifestyle risk factors for cancer and describe how they raise risk.
- Describe genetic risk factors for some cancers and explain that they increase susceptibility rather than guarantee disease.
Cancer exam tips
Marking Points
- State that cancer results from changes in cells, often described as mutations in the genetic material.
- Explain that these changes affect the control of cell growth and division, so the cell cycle is no longer regulated normally.
- Describe the outcome as uncontrolled growth and division, producing a mass of abnormal cells called a tumour.
- Distinguish malignant tumours, which invade neighbouring tissues and spread to other parts of the body, from benign tumours, which do not.
- Link named risk factors, such as smoking, obesity, ultraviolet radiation or viral infection, to an increased chance of the cell changes occurring.
- Explain that a tumour forms when abnormal cells continue to divide rather than being removed or controlled by the body.
- Use the terms cell division, uncontrolled growth, tumour and malignant accurately when describing cancer.
- Benign tumours form when cell division is uncontrolled, producing a mass of abnormal cells.
- The growth remains contained in one area and is usually enclosed within a membrane.
- Benign tumour cells do not invade neighbouring tissues.
- Because they do not spread in the blood, benign tumours do not form secondary tumours elsewhere in the body.
- Benign tumours may still cause harm by pressing on nearby organs or tissues, even though they do not invade.
- Malignant tumour cells are cancer cells that divide in an uncontrolled way.
- They invade neighbouring tissues, disrupting the normal tissue around them.
- Malignant cells can enter the blood and travel to different parts of the body.
- Where they settle, they form secondary tumours, also known as metastases.
- The ability to invade and spread distinguishes malignant tumours from benign tumours.
- Cancer results from uncontrolled cell division caused by changes in DNA, which may form a tumour.
- Lifestyle risk factors include smoking, alcohol, obesity, poor diet, lack of exercise, and ultraviolet radiation.
- Lifestyle factors are largely avoidable or reducible, so they can lower the chance of developing some cancers.
- Genetic risk factors are inherited alleles, such as BRCA variants, that increase susceptibility to particular cancers.
- Risk factors increase probability rather than guaranteeing cancer, so an individual with a genetic risk may never develop the disease.
- A full explanation links a named factor to increased DNA damage or cell division and therefore to a greater chance of cancer.
Examiner Tips
- 💡Use the phrase changes in cells that lead to uncontrolled growth and division, then add detail about tumours to secure the explanation.
- 💡When a question names a risk factor, link it to an increased chance of cell changes rather than to a guaranteed outcome.
- 💡If asked to compare tumour types, give one clear difference such as malignant tumours spread while benign tumours do not.
- 💡Keep answers focused on cells and the cell cycle rather than on treatments, unless the question specifically asks about treatment.
- 💡Use the phrase 'contained in one area' and mention the membrane when describing a benign tumour.
- 💡Contrast benign and malignant directly: contained and non-invasive versus invasive and spreading.
- 💡If asked to explain why a benign tumour is not cancer, state that it does not invade neighbouring tissues or spread in the blood.
- 💡Use the terms 'invade' and 'secondary tumours' accurately when describing malignant tumours.
- 💡Link the spread specifically to the blood when explaining how cells reach distant organs.
- 💡When comparing tumours, state clearly that malignant cells invade and spread whereas benign cells do not.
- 💡Read the command word carefully; if asked to explain, link each factor to DNA changes or uncontrolled cell division rather than just naming it.
- 💡Use the phrase 'increases the risk of' rather than 'causes' when describing any risk factor.
- 💡Include at least one lifestyle factor and one genetic factor when the question asks about both types of risk.
Common Mistakes
- Writing that cancer is a single disease caused by one mutation; correct this by saying cancers result from changes in cells, and several changes are usually needed.
- Saying that all tumours are cancerous; correct this by distinguishing benign tumours, which stay in one place, from malignant tumours, which invade and spread.
- Claiming that a risk factor such as smoking always causes cancer; correct this by saying it increases the risk or chance of the cell changes occurring.
- Describing cancer as uncontrolled cell growth without mentioning division; correct this by including both growth and division of cells.
- Saying benign tumours are harmless in every case; correction: they do not invade or spread, but pressure on nearby tissue can still cause problems.
- Confusing benign with malignant by stating that benign tumours spread in the blood; correction: benign tumours stay in one area and do not form secondary tumours.
- Describing benign tumours as normal cells; correction: they are growths of abnormal cells, even though they remain contained.
- Saying malignant cells spread through the air; correction: they spread in the blood, and also via the lymphatic system, to form secondary tumours.
- Confusing a secondary tumour with a new, unrelated cancer; correction: a secondary tumour is formed from cells that broke away from the original malignant tumour.
- Stating that malignant tumours stay in one place; correction: invasion of neighbouring tissues and spread in the blood are defining features of malignancy.
- Stating that a risk factor causes cancer directly: correct this by saying it increases the probability of cancer developing.
- Confusing genetic risk with a certainty of inheriting cancer: correct this by explaining that inherited alleles raise susceptibility but do not guarantee the disease.
- Listing infections as lifestyle factors: correct this by recognising that while some infections are risk factors, they are not classified as lifestyle choices.