CTSK and lymphangioleiomyomatosis: Similarly, it has been reported that CTSK is also highly expressed in wide spectrum of perivascular epithelioid cell neoplasms (PEComas), including lung.[55] Whether CTSK accumulation in LAM and PEComas would undergo endocytosis facilitated by SNX9 to activate specific intracellular signals for disease progression remains to be further elucidated.