A simplified schematic of proposed IOPI model with the progression of intravasation and extravasation.Note: In low invasive breast cancer, tumor cells (labeled in red) can be seen beginning to accumulate in the ducts, but have not yet broken through the basement membrane, and the invasiveness is relatively low. Whereas in highly invasive breast cancer, tumor cells proliferate in large numbers, break through the basement membrane and invade into the surrounding tissues, showing a stronger degree …