A joint study by UK universities has revealed a correlation between commonly used arthritis drug azathioprine and the development of skin cancer.

The research was conducted by the University of Dundee, Queen Mary University of London and the Wellcome Sanger Institute.

Findings highlighted a link between azathioprine and a mutational signature in a common type of skin cancer called cutaneous squamous cell carcinoma (cSCC).

Azathioprine is an immunosuppressive medication. Alongside arthritis, the drug is widely used for inflammatory bowel disease, vasculitis and organ rejection in patients who have had transplants.

While the drug is already known to increase photosensitivity to UVA light, the latest study showed that it also leaves a molecular fingerprint in skin cancers.

“As with all medications, the risks must be balanced against the benefits.”

University of Dundee School of Medicine dermatology professor Charlotte Proby said: “We recommend all physicians give appropriate advice on UVA avoidance, including year-round sun protection for their patients on azathioprine.”

Researchers added that azathioprine need not be withdrawn or taken off the market. They said that like all medication, the risks should be balanced against the benefits.

They also said that patients using azathioprine can potentially benefit from better sun protection.

Proby added: “As with all medications, the risks must be balanced against the benefits, particularly with the need to treat potentially life-threatening diseases with an effective drug.

“It is important that sun protection, skin surveillance and early diagnosis/lesion removal are part of the routine management of patients on azathioprine.”

Researchers hope that the new findings on the molecular landscape of cSCC and potential targets could help in the development of therapies for the future management of cancer.