Our in vivo experiments performed in NOD/SCID mice provided the advantage to analyze the intrinsic mechanism of tumor progression in the absence of an immune response supporting the importance of the GITR/GITRL axis in tumor progression in nonepithelioid MPM, while GITR/GITRL had no impact in epithelioid MPM in the absence of an immune response. Here, TNFRSF18 is linked to neoplasm.