As TSC2/tuberin protein is expressed by cells that comprise tuberous sclerosis or LAM lesions as well as cells adjacent to the lesions (29), it is likely that TSC2 function is compromised in these mTOR+ MVPCs and may be more important than the presence or absence of protein in the regulation of mTOR signaling (29–31). This evidence concerns the gene TSC2 and lymphangioleiomyomatosis.