miR-105-5p was highly expressed in CSCs and CSCs-exo treatment significantly upregulated the expression of miR-105-5p in BC cells.GPR12 was subsequently verified to be the target gene of miR-105-5p, and overexpression of GPR12 abrogated the effects of miR-105-5p on BC cell growth and metastasis. Here, GPR12 is linked to breast cancer.