PPIG and neoplasm: After intravenous administration of Cyp-PMAA-Fe@MSCs and Cyp-PMAA-Fe@RBCs (RBCs, red blood cell membranes) separately in tumor-bearing mice, Cyp-PMAA-Fe@MSCs group had a 21% stronger fluorescence signal at the tumor site than Cyp-PMAA-Fe@RBCs group, indicating that Cyp-PMAA-Fe@MSCs accumulated more at the tumor site.