A model for homing and peripheralization of HPC by chemoattractants. This model considers: (A) homing of HPC to chemoattractants in the BM microenvironment and (B) mobilization of HPC out of the BM microenvironment when the negative gradient of the BM is broken by administering chemoattractants or known HPC mobilizers, which may act directly or induce expressions of chemoattractants outside of BM disturbing normal chemoattractant gradient around BM-PB system. The presence and concentration of chemoattractants are represented as intensity of gradient in the BM and PB compartment. Direction and size of arrows crossing two compartments respectively indicate the direction of cell migration and relative intensity of migration.