We can use our immune systems to combat cancer
RESULTS from the Cancer Genome Atlas project, which has been running for more than a decade and in which more than 10,000 tumours were examined, are a major step forward in our understanding of cancer and will boost both treatment methods and survival rates dramatically.
The scientists identified many genes which, when mutated or activated fuel cancer growth, while investigating the molecular triggers behind 33 types of cancer, which will allow them to predict how the cancer is likely to develop.
Over the last few years we have been aware that cancers grouped under one type, such as breast cancer, are not a single entity and can develop in different ways through different types of genetic alterations.
The study used many different molecular techniques to investigate genetic changes in tumours, which means that in the future (and in some cases the present) we will be able to target treatment for individuals to the specific mutated genes or other genetic alterations in their cancers.
We have known this for a while but sequencing the DNA in 10,000 tumours and investigating other aspects of these tumours such as chromosome changes has provided a huge amount of information.
ONE important aspect of this work is to chart the immune response to a tumour. The scientists looked at different immune responses to different tumours in relation to their genetic profiles, which gives the potential to improve treatment if the body’s immune response can be helped to attack the tumour.
In the case of melanoma, for instance, we have already helped to improve the immune response to certain melanomas. So we can greatly increase the numbers of people who can be helped due to the new information available.
The research also showed that cancers can be grouped in different molecular types depending on what cell type they start off in. For example, a cell on the surface of the cervix or oesophagus is a squamous cell and turns into a different type of tumour from a cell in, for example, the stomach lining or the breast.
Knowledge of the important “driver” genetic alterations in tumours (those that promote the development of the tumour) allows the development of therapies which deactivate the drivers.
This is already beginning to happen with melanomas and lung cancer: a particular type of gene tends to be mutated in some types of melanoma or lung cancer and we can already target those.
There may be a lot of genetic changes in tumours but just a few of them are driver mutations, which are the important ones that start the tumour off in the first place.
There are all sorts of potential avenues that can develop after that and this information will help us to know how the tumour grows.
For example, we will be able to say of someone not that they just have stomach cancer but that they have a particular sub-type of stomach cancer, making the diagnosis much more specific.
The scientists also looked at the effects of the genes that had been altered or turned on in cancers, and whether they caused cells to die or proliferate. Different tumour types develop along different genetic pathways and knowledge of this will allow scientists to find molecular weaknesses in the cancers which could lead to improved treatments.
Specifically targeting genes like this improves treatments enormously. Once you have very specific treatments they can be really effective.
We know that a certain type of treatment, with “PARP inhibitors” is effective in treating ovarian cancers which have a specific genetic characteristic, so we know that with some people that will be particularly effective. As the information from this study is analysed such specific treatments are likely to become readily available.
Any new drug-related treatment will of course involve clinical trials, which means that there will be some time before they can be used on patients.
But some of the relevant treatments are already in use for other illnesses. Some of the genes that have been identified as mutated in certain cancers are found in other diseases too. So the treatments available for these diseases are already on the shelves and we can start to use them for cancer therapy, if appropriate, quite quickly.
This research means that relatively simple molecular tests will be developed which can be used easily by clinicians, who can then target therapy quickly for the type of tumour.
AT THE moment the relevant tests are very complicated but this new research could make them cheaper and more efficient.
Cancer is not a single disease. And this work has hugely increased our understanding of how complex cancer is. It will improve our knowledge of what is going on in the tumour and how to stimulate the immune response.
It will show us the particular characteristics of certain types of cancer, which genes are altered or turned on, and develop our approach to nullify that particular gene. This is a great step forward and will make us much better at treating cancers in the future, potentially saving many lives.
‘Treatment will be tailored to individuals’