Secondary Science
Post-16
Genetics and Medicine –Breast Cancer in the Family
Supporting information for teachers
PROGRAMME SYNOPSIS
Current genomic research is helping us to understand how genetic and environmental factors affect complex conditions such as breast cancer.
Alison Griffies has a strong history of breast cancer, but no known genetic change has been found in her family to explain this pattern.
Risk of breast cancer is approximately 1 in 10 in Northern European populations making it the most common cancer in women. The vast majority of breast cancer cases are attributable to a complex mix of genetic and environmental factors.
Professor Gareth Evans, a leading expert in breast cancer, describes how genome-wide association studies scan genomes to look for genes that might be associated with the condition. The data from these studies and other research has provided a better understanding of the causes of cancer. It is hoped that this knowledge will be used in the future in prevention programmes for breast cancer and also provide answers for families such as Alison’s.
Whole genome research projects including biobanks also raise ethical and social issues, discussed in the programme by Professor Michael Reiss from the Institute of Education, London.
KEY MESSAGES
Large-scale studies and breast cancer
Genetic differences cannot be said to ‘cause’ the disease; the results provide a probability that an individual will develop the disease.
Breast cancer is a common and complex disease which can be attributed to genetic and lifestyle factors.
Scientists use Genome-Wide Association Studies (GWAS) to investigate the entire human genome. They find differences in genes which correlate with common diseases, e.g. breast cancer.
Scientists work with thousands of DNA samples to ensure that the differences they find are not due to chance alone.
GWAS results provide risk predictions for genetic differences, mutations like BRCA have high risk, but most genetic differences have subtle effects but can act cumulatively.
Large-scale population studies are being used to identify how lifestyle factors influence risk of developing breast cancer.
Results from GWAS will be used in combination with lifestyle risk factors so that in future, doctors hope to be able to provide patients with more accurate risk predictions for developing breast cancer.
Biobanks
UK Biobank is a 25 year project which aims to collect genetic, physiological and environmental information relating to people’s health/disease.
Scientists hope that this will be a useful resource in the future for very large association experiments analysing the interplay between genes and environment.
There are issues associated with using genomic information in healthcare. These include:
1)Is there an obligation for individuals to contribute to this research for the ‘greater good’? Should there be an ‘opt out’ system?
2)Who owns genomic information? Will it be accessible to employers, life insurers? Do people have the right to withhold their genetic data?
3)Will genomics create inequity in health services? E.g. would women at low risk of breast cancer have less frequent screening? Will pharmaceutical companies target drugs to the developed world?
4)Over the counter genetic tests and quality assurance – How can citizens be supported in accessing and interpreting good quality genetic data. What impact will this have on health services?
CURRICULUM LINKS
How Science Works:
Consider applications and implications of science and appreciate their associated benefits and risks
Consider ethical issues in the treatment of humans, other organisms and the environment.
Edexcel GCE Biology
Topic 1
Related to:
12. Describe the factors that increase the risk of CVD
20. Explain why people’s perceptions of risks are often different from the actual risks (including underestimating and overestimating the risks due to diet and other lifestyle factors in the development of heart disease.
15. Discuss how people use scientific knowledge about the effects of diet exercise and smoking to reduce their risk of coronary heart disease.
OCR GCE Biology
Unit F215:
5.1.1e. state that mutations cause changes to the sequence of nucleotides in DNA molecules
5.1.1f. explain how mutations can have beneficial, neutral or harmful effects on the way a protein functions
5.1.2 k. explain that both genotype and environment contribute to phenotypic variation
AQA GCE Biology
3.2.1 Similarities and differences between individuals within a species may be the result of genetic factors, differences in environmental factors, or a combination of both.
3.2.3 Similarities and differences between organisms may be defined in terms of variation in DNA. Differences in DNAS lead to genetic diversity.
USEFUL WEBSITES
Nowgen
Genome British Columbia
National Human Genome Research Institute (USA)
The Genesis Appeal (charity dedicated to breast cancer prevention)
Breast Cancer UK
Nowgen is a leading centre for genetics in healthcare and sets out to inform and improve the practice of genetic medicine. Through the Nowgen Schools Genomics Programme we aim to narrow the gap between genomics research and classroom genetics.