MSLN and mesothelioma: Interestingly, a phase I clinical trial to evaluating the mechanisms of amatuximab in patients with mesothelin-expressing cancers reported an increase in serum CA125 levels in all patients with mesothelioma [16] and subsequently ovarian cancer that was attributed to amatuximab inhibiting the binding of cell associated mesothelin and CA125, thereby preventing the intraperitoneal / intrapleural spread of ovarian cancer and mesothelioma.