PLK1 and breast cancer: The result of the experiment showed that the iMSN/Plk1 + 200c + ICG (+light) group revealed higher inhibition ratio than other groups (iMSN/Plk1 + 200c + ICG (−light), MSN/Plk1 + 200c + ICG, iMSN/NC + ICG, iMSN/Plk1 + NC + ICG, iMSN/200c + NC + ICG) in tumor cell proliferation of orthotopic breast cancer model.