Sylvie Euvrard and her colleagues (New England Journal of Medicine 2012; 367:329) have performed a multicentre randomised trial in patients on a calcineurin inhibitor who had developed at least 1 squamous cell cancer of the skin after renal transplantation. Patients were randomised to either continue on the calcineurin inhibitor or to be converted to sirolimus. There was a significant reduction in the occurrence of subsequent squamous cell carcinomas in the two year follow up period but a considerable number of patients on the sirolimus arm had treatment discontinued because of significant adverse events (including pneumonitis). Nevertheless this does provide further evidence that sirolimus does provide a management protocol for patients with squamous cell carcinomas of the skin after renal transplantation but one would have to accept that there is a very definite risk of serious adverse events. Interestingly renal function remained stable in the two groups at the end of two years.