Research into the causes and prevention of breast cancer | Cancer Research UK
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Research into the causes and prevention of breast cancer

This page tells you about research into the causes of breast cancer and ways of preventing breast cancer.  You can find the following information


A quick guide to what's on this page

Research into causes and prevention of breast cancer

We know that some things can increase the risk of developing breast cancer, such as inheriting faulty genes like BRCA1 or BRCA2. 

Scientists and researchers are trying to find out more about other genetic changes that may cause breast cancer. They are also looking at other factors such as diet, alcohol, and exercise to see if they influence breast cancer risk.  

There is also a lot of research looking into finding ways of preventing breast cancer, including changes to diet. Some research uses particular medicines, such as hormone therapies, to help stop a cancer developing. This is called chemoprevention.

Cancer Research UK supports a lot of UK laboratory research into cancer and also supports many UK and international clinical trials.

You can find detailed information about trials looking at the causes of breast cancer and preventing breast cancer on our clinical trials database.


CR PDF Icon You can view and print the quick guides for all the pages in the Treating breast cancer section



Diet and lifestyle as a cause of breast cancer

A study called The DietCompLyf study is looking at whether diet, complementary therapies and lifestyle factors can affect breast cancer survival. Early results have found that women often changed their diet after being diagnosed with breast cancer. More results will be published as they become available.

Another study is looking at the possible links between diet, lifestyle and breast cancer. In this study, the researchers hope to learn more about how risk factors such as diet and drinking alcohol affect genes in ways that could lead to breast cancer.


Research into faulty breast cancer genes

We know that two important inherited gene faults can increase the risk of breast cancer – BRCA 1 and BRCA 2. But these faulty genes only cause a relatively small number of breast cancers. Specialists think there are lots more genes that don’t carry such a high risk, but are probably carried by more people.

CHEK2 gene

Scientists identified another faulty gene called CHEK2 in 2004. They called this the first low risk cancer gene. In the general population, a faulty CHEK2 gene is rare. But it is much more common in women with cancer in both breasts (bilateral breast cancer).

Research has since found that about 2 out of every 100 women (2%) with breast cancer in both breasts have the CHEK2 gene fault. The scientists think that CHEK2 is interacting with other breast cancer gene faults in these women and giving them a very high risk of breast cancer. They have worked out that women who have close relatives with bilateral breast cancer and the faulty CHEK2 gene have a 1 in 2 risk of getting breast cancer themselves by the age of 80.

As there are only about 2,000 cases of bilateral breast cancer diagnosed each year in the UK, it should be possible to screen these women and find out if they carry the CHEK2 gene fault. If they do, this may mean we can identify other women in their families with this high risk of breast cancer.

Male relatives of women with bilateral breast cancer and a faulty CHEK2 gene also have a higher than average risk of developing prostate cancer. An individual test is not available yet for the CHEK2 gene. If you are having a test for the BRCA genes they may also look for a change in the CHEK2 gene.

EMSY gene

A groups of researchers, including Cancer Research UK scientists, recently found a new gene change called EMSY. This gene switches off the normal BRCA2 gene and allows breast cancer to develop.

Collecting information about breast cancer genes

The EMBRACE breast cancer study is collecting information about people who have inherited the faulty breast cancer genes BRCA1 or BRCA2.

Researchers and doctors are creating a register of families in the UK with a history of breast cancer, and a database of blood samples. They hope that collecting all this information about the genetic make up of these families will help them find other genes involved in breast cancer.

The Generations Study

A charity called Breakthrough Breast Cancer is running a study called the Generations Study. The aim is to try to find out more about the causes of breast cancer, including genes.

The study has recruited 113,000 women living in the UK. It is looking at factors that can increase the risk of developing breast cancer. Participants fill in regular questionnaires and have blood samples taken. The researchers use the blood samples to look for any genes and hormonal factors that may affect breast cancer risk.

We have information about the Breakthrough Generations study

You can find details of studies looking at gene changes and breast cancer risk on our clinical trials database.


Research into breast stem cells

Stem cells are undeveloped (immature) cells that are able to become any type of cell in the body. The body uses stem cells to replace damaged or old cells. We know from research that some stem cells in the breast may be involved in the start of certain breast diseases.

The ABSCS study is looking at samples of breast stem cells from people without cancer and people with different stages of breast cancer. If researchers can understand more about how stem cells in the breast work, they may be able to develop new treatments in the future.


Phyllodes tumours

Scientists are trying to find out more about a rare type of breast tumour called Phyllodes tumours. There is a study to find out which genes might be involved in the development of these tumours, and also why some come back after treatment. You can find information about Phyllodes tumours.

You can also get details of the Phyllodes study. The trial has closed and we are waiting for the results.


Coeliac disease

Coeliac disease (pronounced see-lee-ak) is a disease of the small bowel. People with coeliac disease have an immune or allergic reaction to gluten, a protein found in rye, wheat and barley. This causes inflammation, which over time can damage the lining of the small bowel. This makes it difficult for the bowel to absorb the nutrients we need from our food. People with coeliac disease have to stick to a gluten free diet.

Some research suggests that people with coeliac disease have a lower risk of breast cancer. A research team reported in 2012 that women with coeliac disease had some factors that increased their risk of breast cancer and some factors that decreased their risk of breast cancer. They suggest that the reduced risk of breast cancer is related to menstrual and reproductive factors.

On our clinical trials database you can read about the results of the coeliac disease and breast cancer study.


Medicines for women at high risk

A lot of research has looked at using medicines to try to prevent breast cancer in women who have an increased risk of breast cancer due to a family history or having a faulty gene. The research is continuing.

Hormone therapies

Doctors have looked into using tamoxifen or other hormone blocking drugs such as anastrozole (Arimidex) to lower breast cancer risk in women with a strong family history. Using drugs to reduce cancer risk is called chemoprevention.

We have information about different types of hormone therapies, including tamoxifen and anastrozole (Arimidex).

Tamoxifen is a drug that has been used to treat breast cancer for more than 35 years. It works by stopping oestrogen from triggering hormone receptors in breast cancer cells. In trials, some women at high risk of breast cancer took tamoxifen for 5 years to see if it reduced their risk. In early 2013 Cancer Research UK looked at the results of all these trials together. They showed that tamoxifen can lower risk of breast cancer in women at high risk.

The benefits of tamoxifen in preventing breast cancer seem to last for at least 5 years after the treatment has ended. The researchers estimate that 1 breast cancer would be prevented for every 42 high risk women who took the drug for 5 years.

In 2014 the IBIS1 trial also reported that tamoxifen can lower breast cancer risk. You can read the results of the IBIS1 trial on our clinical trials database. 

The TAM-Prev trial looked at the number of premenopausal women with a high risk of breast cancer who would consider using tamoxifen to prevent it. The researchers found a number of factors that influenced the women in making their decision, including the impact of possible side effects. You can read the results of the TAM-Prev trial.

Raloxifene, arzoxifene, and lasofoxifene are drugs similar to tamoxifen and are used to treat bone thinning (osteoporosis). In trials, these drugs also reduced the number of women who developed breast cancer. These drugs do have side effects though. They increase the risk of blood clots and strokes. Tamoxifen also slightly increases the risk of womb cancer.

Although tamoxifen and raloxifene reduce breast cancer risk in women at high risk, it is not clear whether this reduces breast cancer deaths. Research is continuing to try to find this out.

We have information about raloxifene.

Anastrozole (Arimidex) is a breast cancer hormone therapy that was researched in the IBIS 2 prevention trial. The results were published in the Lancet in 2013.

The trial compared 5 years of anastrozole with a dummy drug (placebo). There were 4,000 women who took part, all at high risk of breast cancer. Taking anastrozole reduced the risk by more than 50% in these women. Anastrozole caused fewer side effects than tamoxifen.

The researchers said that anastrozole works better than tamoxifen for preventing breast cancer. They recommend that it should be considered in the future for women at high risk.

Researchers are testing other hormone drugs to see if they can reduce the risk of breast cancer but give fewer side effects. These include exemestane (Aromasin), and tibilone.

Current UK advice for women at higher risk of breast cancer

The National Institute for Health and Care Excellence (NICE) recommends that women at high or moderate risk of breast cancer should talk to their doctor about taking either tamoxifen or raloxifene for 5 years, alongside their other options. They do not recommend these drugs if you have had a blood clot or are at risk of developing one.


Supporting research into breast cancer

There is a lot of research into the causes of breast cancer and into finding ways of preventing breast cancer. Cancer Research UK supports many UK and international clinical trials.

You can find information about UK clinical trials on our clinical trials database.

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Updated: 21 October 2014