PDGFRB and glioblastoma: However, the efficacy of CL4, used in combination with the anti-PDGFRβ aptamer, was also extended to a PDGFRβ-positive GBM primary cell line lacking endogenous EGFRwt and engineered to express EGFRvIII (VS-GB/EGFRvIII), thus indicating the relevance of blocking both EGFRvIII and PDGFRβ also in the absence of the wild-type receptor.