Figure 3. Pathogenesis of AIN. The process begins with the recognition and subsequent processing of the putative antigen by dendritic cells that endocytose, process, and express the peptides on their surface MHC II molecules, which they then present to the naïve lymphocytes in the regional lymph nodes. See text under Pathogenesis for the subsequent course of events. EMT = epithelial mesenchymal transition.