ALB and neoplasm with perivascular epithelioid cell differentiation: Interestingly, therapeutic drug monitoring was found to be a critical aspect during sirolimus treatment.240 Siromimus received FDA approval in the year 2015 for lymphangioleiomyomatosis based on the efficacy reported in clinical trials (ClinicalTrials.gov number, NCT00457808, and NCT00414648).241,242 Nab-sirolimus (albumin-bound nanoparticles-based sirolimus formulation) displayed a strong antitumor effect in cases with perivascular epithelioid cell tumors (PEComa).