A link between the level of active DNA repair genes in melanoma tumours and the effectiveness ofchemotherapy for skin cancer patients has been established for the first time by a team of scientists.

The study, part-funded by Cancer Research UK and published in Clinical Cancer Research on Friday, found that higher levels of DNA repair genes in melanoma tumours were associated with a poorer response to chemotherapy.

It is the first time that genes involved in DNA repair have been identified as a possible predictive marker for a patient's response to chemotherapy for melanoma.

The study looked at 502 cancer-related genes in the tumours of 472 patients – making it the largest piece of research to look at genes in melanoma.

The results could potentially help doctors decide the most effective treatment earlier on for a melanoma patient, increasing their chance of survival.

Professor Julia Newton-Bishop, lead author of the study who is based in the Cancer Research UK Centre at the University of Leeds, said: "This paper identifies so-called biomarkers - changes within the tumours themselves which predict how patients will respond to treatment.

"Our study found that the increased expression of DNA repair genes in melanomas predict poorer outcome overall and provide preliminary evidence that those patients whose tumours have lower levels of the genes may respond better to standard chemotherapy for melanoma."

The research supports the theory that high levels of DNA repair genes in melanoma tumours constantly repair the damaging effects of chemotherapy to the DNA leading to further multiplication of cells.

This meant the treatment was inefficient at killing cancer cells and stopping tumour growth.

Sara Hiom, director of health information at Cancer Research UK, said: "Chemotherapy can be an unpleasant experience for some patients. This study shows that a genetic marker could help doctors assess whether a melanoma tumour will be resistant to chemotherapy and ensure that a patient receives a treatment that will be the most effective for them.

"The results showing the genetic link in melanoma tumours to chemotherapy were from a small sample. Scientists now need to test this finding with a larger number of melanoma tumours to see whether this genetic marker can actually be used by doctors to help treat patients."

Source: Cancer Research UK