No human evidence. There is no credible evidence that Protopic ointment causes skin cancer in humans. There is a warning label in the package insert, but it is based on data from mice who were *fed* huge quantities of the active ingredient. So if you are a mouse who loves to eat protopic, you might have a problem; if you are a human who is applying it to your skin in reasonable amounts, don't worry about it.
Some risk perhaps. Tacrolimus is in a class of medications called topical calcineurin inhibitors. It works by stopping the immune system from producing substances that may cause eczema. The fda did offer a warning about the risk of skin cancer in 2005. This concern is based on information from animal studies, case reports in a small number of patients, and how these drugs work. Discuss with your doctor.
I believe it is. Tacrolimus given systemically for immunosuppression can cause the virus-induced hyperplasias that mimic cancer but generally resolve on its withdrawal. It strains credulity to think this could apply to the common anti-eczema ointment. Br. J. Derm. Sept 2011 actually looked at this hard and probably the excess lymphomas had been misdiagnosed as common eczema rather than caused by the tacrolimus.
Protopic (Tacrolimus) Although there is a theoretical concern that topical immunomodulatory therapy with tacrolimus and pimecrolimus may increase the risk of cancer, there is no evidence to date to suggest an increased risk of cutaneous or visceral cancer. The european agency for the evaluation of medicinal products has not recommended any change to labelling or approval of these topical agents.