In resistant malignant pleural mesothelioma cells, the Ras/ERK1/2 axis promotes the phosphorylation of STAT3 on serine 727 and increases the transcription of IDO; this event is prevented by ZA and reduces the ex vivo expansion of immunosuppressive Treg cells [16]. The gene discussed is STAT3; the disease is malignant pleural mesothelioma.