A drug used to treat inflammatory bowel disease, arthritis and vasculitis as well as to prevent organ rejection in transplant patients has been found is an important contributor to skin cancer.
The study is carried out by the University of Dundee, Queen Mary University of London and the Wellcome Sanger Institute.
The research identified a `strong case for an association’ between the drug azathioprine and cutaneous squamous cell carcinoma (cSCC), a common form of skin cancer.
More than 40,000 new cases diagnosed annually in the UK, with significant health economic implications.
It was already known that use of azathioprine leads to increased photosensitivity to UVA light, probably contributing to development of skin cancers.
This new study finds that use of azathioprine leaves a molecular fingerprint in skin cancers, further implicating it in cSCC development.
In the study, the researchers ran analysis of cSCC tumors from 37 patients, many of whom had been on azathioprine.
They found a new mutational signature, Signature 32, which correlated with time on azathioprine therapy.
Researchers suggest all physicians give appropriate advice on UVA avoidance including year-round sun protection for their patients on azathioprine.
But this does not necessarily mean the withdrawal of azathioprine.
“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,” one author said.
“It is important that sun protection, skin surveillance and early diagnosis/lesion removal are part of the routine management of patients on azathioprine.”
It’s also important for people to protect their skin from the sun when it’s strong, especially if they burn easily or are taking medications which make them more sun-sensitive.
The most effective protection is to spend time in the shade and cover up with a hat, long-sleeved top and sunglasses.
For the bits you can’t cover, use sunscreen with at least 4 stars and SPF 15 or higher for protection against both UVA and UVB rays.
Importantly, this new study also reveals the molecular landscape of cSCC and highlights potential targets that may be developed for future therapeutic approaches to manage cSCC.
Although patient numbers were small and these findings should be verified in a larger independent cohort, this molecular study provides a strong case for an association between this novel mutational signature and long-term azathioprine use.
The study is published in Nature Communications.
Source: University of Dundee.