This invited editorial article aims at reporting progress about the enhanced permeability and retention effect (EPR for short), starting from a recent Special Issue in the Journal of Personalized Medicine (namely, "EPR Effect-Based Tumor Targeted Nanomedicine") and focusing specifically on one of these contributing articles, a review from Jun Wu entitled "The Enhanced Permeability and Retention (EPR) Effect: The Significance of the Concept and Methods to Enhance Its Application", which has recently acquired the rank of a highly cited paper [...].