Home

Biology

Global challenges

Cancer and its risk factors

Select Lesson

Exam Board

Select an option

Biology practicals

Investigating specimens using microscopes

Investigating the effect of pH on amylase activity

Investigating osmosis in potatoes

Investigating limiting factors of photosynthesis

Investigating the rate of respiration

Using field-work techniques

Ecosystems and material cycles

Ecosystems, competition and environmental changes

Human impacts on biodiversity

Conservation and maintaining biodiversity

The carbon cycle

The water cycle

Obtaining potable water

The nitrogen cycle

Exchange and transport in animals

Specialised exchange surfaces

Human circulatory system

Aerobic and anaerobic respiration

Animal coordination, control and homeostasis

The human endocrine system

Hormones: adrenaline and thyroxine - Higher

Hormones in human reproduction

Treating infertility - Higher

Homeostasis and blood glucose

Plant structures and their functions

Photosynthesis and limiting factors

Factors limiting the rate of photosynthesis - Higher

Water and mineral transport in plants

Health, disease and the development of medicines

The relationship between health and disease

Communicable disease

Sexually transmitted infections

How the body fights disease

Vaccination, immunisation and medicines

Drug development and testing

Non-communicable diseases

Calculating BMI and the waist-to-hip ratio

Cardiovascular disease and treatment

Natural selection and genetic modification

Evolution by natural selection

Fossils as evidence for evolution

Classifying living organisms

Selective breeding

Uses and evaluation of genetic engineering

The process of genetic engineering - Higher

Genetics

Meiosis, sexual and asexual reproduction

DNA: structure, genes and chromosomes

Inheritance and genetic diagrams

Inherited disorders

Types and sources of variation

The human genome project

Cells and control

The cell cycle and stages of mitosis

Cell differentiation, stem cells and ethics

The nervous system and the reflex arc

Key concepts

Eukaryotic and prokaryotic cells

Specialised animal and plant cells

Types of microscopes and calculations

Enzymes

Transport systems in cells

Working scientifically

The scientific method

Science communication and ethics

Evaluating risks and hazards

Collecting data

Processing and presenting data

Units and equations

Structuring a scientific report and drawing conclusions

Uncertainties and evaluations

Practical skills

Measuring techniques

Safety and ethics

Designing experiments

Methods of heating substances

Working with electronics

Random sampling and sampling methods

Comparing results using percentage change

Explainer Video

Tutor: Priya

Summary

Cancer and its risk factors

In a nutshell

Cancer is a disease caused by uncontrolled cell growth and division. There are certain risk factors that can increase the risk of developing some cancers.

Cancer

Cancer is a disease in which changes in some of the body's cells can result in uncontrolled growth and division. This leads to a mass of abnormal cells, also known as a tumour. There are two types of tumours: begin and malignant.

Benign tumours	Malignant tumours
Stay in one location	Spread to other parts of the body by breaking off and travelling in the bloodstream.
Do not invade other body parts	Can invade healthy tissues and form secondary tumours.
Not dangerous or cancerous	Dangerous and can be fatal. These are cancers.

Risk factors

Over the years, research has identified many factors that increase the risk for certain cancers. These include both genetic and lifestyle factors.

Lifestyle risk factors

Smoking	Cigarette smoke is linked to many cancers, including cancers of the lungs, mouth and throat.
Obesity	Being obese can put people at risk of over twelve different types of cancer.
Viral infection	Getting infected by certain viruses can increase the chance of some cancers. Example HPV virus
UV exposure	Exposure to UV radiation (which is produced by the sun) has been linked to developing skin cancer.

Genetic risk factors

Parents pass on their genes to their offspring. Occasionally, an individual may inherit faulty genes. These genes increase the risk of developing cancer.

Example

Inheriting a mutation in the $BRCA1$ gene can increase a person's risk of developing breast cancer.

Improvements in cancer treatment

Nowadays, people have a greater chance of surviving cancer. This is due to an improvement in treatments, the ability of doctors to diagnose cancer earlier, increased screening for cancer, and a greater awareness of the risk factors for cancer amongst the general population.

Learn with Basics

Length:

Unit 1

How the body fights disease

Unit 2

The relationship between health and disease

Jump Ahead

Optional

Unit 3