Myeloma is a cancer of the immune system, with around 4,000 new cases diagnosed each year in the UK. In affected people, blood cells called plasma cells grow uncontrollably in the bone marrow and become stuck there, disrupting normal blood cell production. It can be very painful, and affects bones in multiple parts of the body.
People diagnosed with myeloma are offered tests to work out whether their disease is high or low risk. These tests are crucial for informing decisions about treatment, but they could be made even more accurate.
This new study, published in the British Journal of Haematology, could help improve risk testing in the future by adding miRNA analysis to current tests. It was led by Professor Gareth Morgan, Professor of Haematology at The Institute of Cancer Research, and Head of the Myeloma Unit at The Royal Marsden NHS Foundation Trust.
MiRNAs help control whether genes are switched ‘on’ or ‘off’ in our cells. Like proteins, they are produced from genetic code within our DNA. Coding sequences for miRNAs with related tasks often sit in ‘clusters’ on our chromosomes, the strands of DNA which sit in the nucleus of our body’s cells.
In the study, Professor Morgan’s team tested samples from almost 2,000 myeloma patients enrolled on the Medical Research Council’s Myeloma IX study, a clinical trial. Their aim was to look for specific miRNAs that could show whether a patient had higher or lower risk myeloma.
Using a technique called genomic sequencing, Professor Morgan’s team found three clusters of miRNAs linked with high risk myeloma – two on the X chromosome, and one on chromosome 13. The patients with the worse survival odds – those who, over time, were more likely to die of myeloma – had more of these miRNAs than those who lived with myeloma for longer. It’s possible that looking at levels of these miRNAs in patients could make it easier to spot the patients at highest risk.
The team also discovered other important miRNAs, showing that patients deemed low risk by current tests actually fall into at least two different categories. The researchers found key differences in miRNA signatures in ‘low risk’ patients, with one group much more likely to suffer worse outcomes. The results show the existence of a third, ‘intermediate’ group of patients in myeloma who may need more urgent treatment than they currently receive.
Professor Morgan said: “We’re pleased to have found new links between miRNAs and myeloma. Our next challenge is to develop a test to use in the clinic, which could in the future become an important part of routine care.
“We also need to take our findings to the next stage, which is to find out more about the actual role of these miRNAs in the development of cancer. One exciting thing about the emerging field of miRNA studies is the promise of developing possible new drugs to target them. Some of the miRNAs we linked with myeloma have already been implicated in other cancers, and it’s certain that at least some miRNAs are playing an active role in causing cancer.”