Fig. 1. Disruption of cell polarity and tissue disorganization is a hallmark of advanced epithelial tumors. (A) Normal simple epithelium comprises a monolayer of individual cells that display distinct apical-basal polarity. Cells are tightly packed and connected to each other by the apical junctional complexes (blue), which separate apical (red) and basolateral (green) membrane domains. (B) Cells in high-grade epithelial tumors display loss of apical-basal polarity and overall tissue disorganization.