PTPN22 and neoplasm: The nine amino acid cyclic LyP-1 homing peptide can bind specifically to the P32 cell surface receptor, which is overexpressed by tumor cells and tumor-associated LECs, whereas LyP-1 cannot bind normal LECs.404 Song et al.405 produced LyP-1 peptide-modified 131I-labeled dendrimers that exhibited good cytocompatibility.