T22-GFP-H6-FdU depletes CXCR4+ cancer cells from SW1417 CRC tumor tissue after a 100 µg single dose administration. Note the reduction in CXCR4+ cell fraction in the tumor 24h after injection, their almost complete elimination at 48h and the re-emergence of CXCR4+ cells 72h post-administration, using anti-CXCR4 IHC. In contrast, the CXCR4+ cancer cell fraction (CXCR4+ CCF) in tumor tissue remains constant along time after free oligo-FdU treatment. The three day time-lapse for CXCR4+ tumor cell re-appearance defines the dosage interval used in a repeated dose schedule of nanoconjugate administration in the experiments to evaluate its antimetastatic effect. (N=5: 5 mice/group; 1 samples/mouse). Scale bar, 50 µm. Data expressed as mean±s.e.m 