TGM2 and melanoma: It also displays GTPase, ATPase, protein kinase and protein disulfide-isomerase activity.9, 10, 11, 12 In addition, TG2 mediates the interaction of integrins and syndecans13 with fibronectin and crosslinks proteins of the extracellular matrix, when it is externalized from cells.14 TG2 overexpression has been observed in many tumors, including pancreatic, breast, colon, ovarian, non-small cell lung cancers, glioblastoma and melanoma,15, 16, 17, 18, 19, 20 whereas no data are present in literature concerning its expression and function in MPM.