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Tracing cancer with a simple blood test

Thanks in part to the persistence of a Leiden research group, cancer could be detected in the near future with just a single drop of blood. Not only can the diagnosis be determined at an earlier stage, but the blood test is also cheap, fast and patient friendly. The first results of this method seem promising.

For many years, the research team of Rob Tollenaar, professor of Surgery - working at the Oncological Surgery department of LUMC - and Wilma Mesker, principal researcher in the same department, have been swimming against the current. Few experts in the world believed that cancer could be detected at an early stage with a simple blood test. But the Leiden researchers were convinced that this should be possible by providing insight into the effects of proteins in the blood that have gone awry. And gradually this indeed seems to be the case. ‘However, we are still very much searching,’ says Tollenaar. ‘The black box surrounding cancer-specific proteins is proving difficult to decipher. Nevertheless, on the basis of our first research results, I dare to think about the clinical application of our blood test.’

Most sceptics now seem to also be convinced. This is confirmed by the growing number of research groups that are developing blood tests. This confidence is also mirrored financially. Whereas until recently the researchers had to fund their research via crowdfunding because the established financiers did not dare touch such an undertaking, now more and more subsidy applications are being honoured by funds, patient organisations and the government. ‘If our blood test is truly applicable on a large scale, you could certainly call it ground-breaking,’ says Mesker. ‘The test could then replace various population studies or serve to supplement them.’


The blood test is based on the fact that a copy is made of an active gene (RNA) that, when stored in the cytoplasm, is translated into a protein. Humans can’t live without proteins; our bodies use them, among other things, as building blocks, fuel, enzymes and antibodies. An important characteristic of proteins is that the immune system clears away cancer cells. Changes somewhere in the transformation process from DNA to RNA to protein form the basis for tumour formation. For this reason, research is being conducted all around the world to detect cancer at the DNA, RNA and protein levels.

‘We are focusing on the proteins,’ Mesker states. ‘Because they indicate the active and current status of a mutation; DNA is static, RNA is the workhorse, but proteins can allow you to deduce what happens after the mutation in the body. Once extracted from the blood serum, the proteins can be analysed. Observed abnormalities, as we now know, indicate tumour formation or a precursor to it. Tollenaar adds: ‘We are now ready to investigate which cancer-specific proteins are characteristic of more aggressive disease development and why. If we can also deduce that using our blood tests, we can not only detect tumour formation, but also treat it in a more targeted manner.’

Read the entire interview with Rob Tollenaar and Wilma Mesker about the development of this blood test in the January issue of our alumni magazine Leidraad >