MTOR and squamous cell carcinoma: In NMSC, switching from calcineurin-based immunosuppression (e.g., tacrolimus and ciclosporin) to a mammalian target of rapamycin (mTOR) inhibitor (e.g., sirolimus and everolimus) in renal transplant recipients with a previous squamous cell carcinoma is associated with prolonged tumour-free survival and significantly fewer cutaneous squamous cell carcinomas at two years [23].