Paving the way to personalised medicine

Hopes are that one day, with a person’s total genome in hand, doctors will be able to pinpoint exactly which cancer medications would be most effective for that particular patient. Though this personalised medicine scenario is still a long way off, researchers from the Netherlands Cancer Institute (NKI) and TU Delft (Pattern Recognition and Bioinformatics Section), published positive news last month in the scientific journal Nature Medicine that brings this dream a little closer.

Cancer is caused by DNA errors that accumulate in our cells throughout our lives. In recent years, many techniques have been developed to detect DNA abnormalities in tumours, in the wake of which an increasing number of drugs were designed that specifically target the effects of these DNA defects.

One of these techniques – a costly but very effective one – simply involves reading out the complete genome (the complete DNA sequence) of tumours. This is called Whole Genome Sequencing (WGS) and is a technique widely used by the Netherlands Cancer Institute (NKI). Last month, NKI and TU Delft researchers showed that this technique is even more powerful in detecting defects and potential targets for medicines than previously thought.

Pressure is mounting to make DNA screening available
The Netherlands is at the forefront in the research field of whole genome sequencing, mostly because a philanthropic organisation (Hartwig Medical Foundation) is paying for it’s use in the NKI amongst others. For the last few months, health insurance companies have reimbursed WGS for a small subgroup of cancer patients with a metastasised form of the disease.

However, there is an ongoing political discussion about whether WGS should be reimbursed for more patients with metastatic cancer, such as those who do not have any regular treatment options left. Hence, the publication of the article is timely. Pressure is mounting to make DNA screening available to more cancer patients.

The use of WGS has two advantages. At the individual level, with a complete overview of a person’s tumour DNA, doctors can more easily decide what treatment options might work. At a higher level, enlarging the database of cancer genome sequences enables researchers to search ever more effectively for new drug targets.

‘This can speed up the widespread application of precision medicine’

“At the moment insurers are worried that a single WGS analysis may be insufficient and that it would have to be repeated over and over again because the DNA of tumour cells changes over time. So they don’t want to reimburse it because it would be too costly,” says Joris van de Haar, physician at the NKI and the first author of the study. Van de Haar conducted the research under the guidance of TU Delft Professor of Computational Cancer Biology, Lodewyk Wessels, and others. “But we have now shown that multiple WGS profiles are rarely necessary because DNA mutations that are relevant for selecting treatment are actually very stable, even though the rest of the tumour’s DNA does indeed change rapidly.”

Wessels too is enthusiastic. “This discovery makes it much more attractive to perform WGS analyses and that, in turn, can speed up the widespread application of precision medicine.”

Wessels adds that research on employing artificial intelligence to integrate different data types – like DNA profiles, other molecular profiles, information on tumour pathology, and images derived from MRI or CT scans – is also taking off. “At the moment we are setting up a research project revolving around artificial intelligence for the prediction of therapy response. This type of research will also bring precision medicine closer.”