Strikingly, Melo et al. [83] reported 100% specificity and sensitivity values to distinguish patients with early and late stage PC from cancer-free controls (patients with benign pancreas disease and healthy individuals) based on the detection in circulating exosomes of a single protein molecule, cell surface proteoglycan glypican-1 (GPC1). The gene discussed is GPC1; the disease is pachyonychia congenita.