MTOR and neoplasm with perivascular epithelioid cell differentiation: Because activation of the mTOR pathway is implicated in PEComa, mTOR inhibitors (sirolimus, everolimus, and tasirolimus) are often the first-line treatment for metastatic PEComa, with somewhat better PFS of 9 months and response rates of 40% in case series [81,83,84,85].