Based on the evidence that the activation of downstream RTK signaling pathways, including PI3K/AKT and RAF/MEK/MAPK cascades, seems to be crucial in both malignant pleural [22] and peritoneal [10] mesothelioma, we evaluated the effect of miR-34a reconstitution on the phosphorylation status of AKT and ERK1/2 in DMPM cell lines. Here, MAPK3 is linked to mesothelioma.