03/02/2016 16:24 GMT | Updated 03/02/2017 05:12 GMT

Our Project Transforming Medicine for Cancer Patients Is at the Cutting Edge of Science

The 100,000 Genomes Project aims to transform medicine for people with cancer and rare diseases. It's unparalleled - there is no other DNA sequencing project this big in a national healthcare system. We aim to bring precision medicine to patients in the NHS, using genomic testing to aid in getting the right drug to the right patient at the right time.

Cancer is a genomic disease. It's caused by changes in our DNA, our genome, which make cells grow and divide uncontrollably. We are sequencing the genomes of cancer patients - that is reading the 3.2billion letters of DNA of their genetic code - both from tumour and healthy cells. By comparing the two we will be able to understand more about what is causing their cancer and which treatments might work best.

It's a huge challenge. The 100,000 Genomes Project is at the cutting edge of science.  No-one has ever attempted whole genome sequencing at this scale before, nor tried to establish it as part of everyday medical care in hospitals.  We have always known that we would encounter challenges along the way and have overcome many already, paving the way for sequencing to become normal NHS care in the future. 

One example of a challenge we face is with the quality and quantity of DNA we can extract from cancer samples collected routinely for patient care.  The cancer cells are taken from tiny pieces of the tumour removed at biopsy or during surgery. Normal analysis of cancer tissue involves looking at the cells down a microscope. To do this, these pieces of tissue would typically be preserved in formalin ('formalin fixed') and then embedded in wax blocks ('paraffin embedded'). FFPE for short. A pathologist then slices the block very thinly and looks at each slice under a microscope to make the diagnosis of cancer based on how the cells look.

But DNA does not react well to being heated and immersed in chemicals. It may become fragmented and bits 'lost' or changed. An alternative is to use freshly frozen tissue. The fresh frozen method gives better quality DNA, but is not suitable for every tumour type, and collection is not currently practical in big busy operating theatres and pathology departments. We are working through these challenges and exploring new ways of handling tissue. Firstly, around how to make it easier to collect high quality fresh frozen tissue as part of routine practice. Secondly, how to change the FFPE pathway to reduce the DNA damage. Our overall aim is to drive up quality of cancer DNA samples in the NHS. This will enable us to move to a new era in which cancer diagnosis, prognosis and management is defined by integration of a series of molecular and genomic tests, rather than just based on knowing which organ the tumour arose in and what the pathologist saw down the microscope.

As well as setting up whole genome sequencing in the NHS, we are enabling medical research. Data from a patient's genome, together with information from their health records is collected. It is de-identified (name and other personal details are removed) and is available for researchers. This is a huge resource, giving scientists the power to undertake a range of complex analyses. We are working with a clinicians and academics from around the world. We plan work alongside ongoing clinical trials, so that whole genome sequencing data can be added, bringing more understanding of how response to a particular drug is influenced by changes or signatures in the DNA. Ultimately, analyses of these genomic data along with the clinical data may identify new molecular targets by which to develop new treatments for cancer.

Precision medicine is already having an impact on some cancer patients, who are benefitting from newly-developed, targeted treatments such as the skin cancer drug vemurafenib. We hope that, one day, treatments based on the specific characteristics of the tumour, including the genetic make-up, can be offered to all patients.

The project was set up by government and is funded by the Department of Health.