AMLs are benign kidney tumors containing smooth muscle cells, blood vessels and fat cells.6 These tumors are used to develop cell lines that can serve as models for LAM, as it is difficult to establish cell lines from pulmonary LAM cells.7 Here we used the AML cell line, 621, which is derived from a LAM patient and is deficient in TSC2.7 Having already shown that FTS inhibits the growth of TSC2-deficient rat ELT3 cells and inhibits Rheb but not Ras in those cells,14 we now wanted to substantiate those observations in a human model. The gene discussed is AKTIP; the disease is lymphangioleiomyomatosis.