Among patients with mesothelioma, those with MPM tended to be older (median age 72 years [range, 42 to 85]) than patients with peritoneal disease (median age 59 years [range, 51 to 65]), with shorter median time from initial pathologic diagnosis to first dose of brentuximab vedotin (13.3 months versus 60.7 months) and higher median CD30 expression level (50% versus 10%). This evidence concerns the gene TNFRSF8 and mesothelioma.