 Recently, rapamycin Rapamune, Wyeth, an FDA-approved drug for use in orthotopic transplant recipients, was successfully used in an off-label study of 5 individuals with a related condition called tuberous sclerosis in which the patients had subependymal giant cell astrocytomas that caused significant and insidious neurological problems such as hydrocephalus and seizures Franz, et al. 2006. All astrocytoma lesions exhibited regression with treatment of oral rapamycin and in one case, necrosis. Treatment was well tolerated and may offer an alternative to operative therapy in tuberous sclerosis. Tuberous sclerosis is caused by germline mutations in the tuberous sclerosis 1 or 2 genes. These genes encode proteins that function downstream of STK11, the gene that is mutated in Peutz-Jeghers Syndrome. Mutations of STK11 or TSC12 leads to activation of mTOR mammalian target of rapamycin. Dysregulation of mTOR has been demonstrated in several types of cancers and clinical trials are underway to see if inhibition of mTOR will be of benefit to a variety of cancer patients. A recent trial showed efficacy of everolimus in advanced renal cancer Hudes, et al. 2007. 