Using a simple blood test to predict whether melanoma will return

Professor Richard Marais

Melanoma is a form of cancer that develops from pigment-producing cells in the skin. Since the 1970s, survival for this disease has almost doubled and now 90% of people diagnosed with melanoma will survive for 10 years or more. This is a tremendous achievement, but unfortunately the nature of melanoma means that for some people it can come back after initial, seemingly effective treatment.

Professor Richard Marais is director of our CRUK Manchester Institute, co-director of the CRUK Manchester Centre and a world-leading expert in melanoma research. His team has discovered that survival for skin cancer patients could be significantly improved thanks to an ‘early warning’ blood test that could predict whether the disease is about to return.

As a tumour develops and grows, old cancer cells die and release their DNA into the patient’s bloodstream. Professor Marais’ blood test detects this DNA, looking for two key genes: BRAF (pronounced bee-raf) and NRAS (pronounced en-ras). Harmful mutations in BRAF and NRAS occur in 70% of malignant melanoma cases and the team have recently found that patients whose blood tested positive for these genetic mutations were much more likely to see the cancer return within a year of surgery.

These findings are very encouraging: if we can use tumour DNA in the blood to accurately predict if a cancer is going to come back, it could help doctors decide which patients are at most risk and could therefore benefit from new therapies – something we are not capable of doing currently. Detecting recurrence and delivering treatment early will dramatically reduce the risk of the cancer spreading elsewhere in the body, transforming the outlook for people whose melanoma has returned.

One of Professor Marais’ greatest breakthroughs was showing how a faulty BRAF gene is responsible for the development of around half of all malignant melanomas. This led to the development of the drug vemurafenib, a targeted therapy that blocks the cancer-causing activity of this gene and the first precision medicine for people with this type of melanoma. In 2018, Professor Marais was presented with the Society for Melanoma Research’s Outstanding Research Award for highly impactful, major discoveries in the field of melanoma over the past five years.