NECTIN4 and non-small cell lung carcinoma: Although our immunohistochemical and immunofluorescent analyses demonstrate substantial Nectin-4 expression in normal lung tissues, our in vivo PET imaging and ex vivo biodistribution results indicate clear and significant differentiation between tumor tissue (NSCLC xenografts) and adjacent normal lung tissues, may result from several factors: higher density and accessibility of Nectin-4 antigen; altered perfusion and vascular permeability; fragment-based pharmacokinetics.