MTOR and kidney neoplasm: Another hypothesis is that metastatic RCC in BHD patients is more sensitive to tyrosine kinase and mTOR inhibitors such as sunitinib and everolimus (two recently-developed drugs that are now routinely used in the treatment of metastatic RCC), as suggested for example by the mTOR signalling pathway activation seen in kidney tumours associated with the syndrome, but that would not account for the good prognosis of cases 13851 and 22973 who received no systemic treatment [14].