This study demonstrates that switching from calcineurin inhibitors to sirolimus had an antitumoral effect in kidney-transplant recipients with cutaneous squamous-cell carcinomas and may have implications concerning immunosuppressive treatment of such patients. Skin cancers affect more than half of organ-transplant recipients during their long-term course. 1 Several studies have shown that after a first cutaneous squamous-cell carcinoma, multiple subsequent skin cancers develop in 60 to 80% of kidney-transplant recipients within 3 years. 2 , 3 Transplant recipients share common risk factors with the nonimmunosuppressed population, 4 but the specific tumor burden of such patients is linked to the immunosuppressive medications used. 5 , 6 A decrease in cutaneous carcinogenesis after the reduction of immunosuppression has been reported. 7 Consequently, changes in immunosuppression are frequently made in patients with skin cancer, although there is currently no consensus on the level . . .