Glypicans (GPCs) comprise a family of heparin sulfate proteoglycans (HSPGs), which attach to the exocytoplasmic domain of the cell membrane by a glycosylphosphatidylinositol (GPI) anchor.100, 101 GPC1 is overexpressed in human PC, and expression of the antisense sequence can apparently decrease the tumorigenicity of PC cells.102 A study by Melo et al. reported that high levels of GPC1+ circulating exosomes (crExos) were found in serum from 190 PDAC patients relative to the levels in healthy donors (P<0.0001) and that GPC1+ crExos contained oncogenic KRASG12D. The gene discussed is GPC1; the disease is pachyonychia congenita.