MTOR and pleural mesothelioma: Considering recent observations that Efemp1 can easily be detected in serum of patients with pleural mesothelioma and that high serum Efemp1 levels discriminates asbestos-exposed persons without mesothelioma from asbestos-exposed persons with mesothelioma [39], points to an avenue to include Efemp1 serum levels as a biomarker in trials with PI3K-mTOR inhibitors in PDAC.