Systemic administration of 4PD loaded with shRNAs specific for CCR1, 2, 5 and 7 to 4T1 bearing mice significantly (p<0.001) delayed tumor progression and decreased the number of lung metastases, whereas the corresponding scrambled shRNAs (SCR1, 2, 5, and 7) had no effect (figure 2A). Here, CCR1 is linked to neoplasm.