TNF and primary central nervous system lymphoma: This may be bypassed by fusing TNF through its N-terminus to CNGRCG, a tumor vasculature-homing peptide that recognizes an isoform of membrane-bound aminopeptidase N (CD13) that is upregulated in the neovasculature of many solid tumors [74,75], including the vasculature of glioblastoma and primary CNS lymphoma [75,76,77].