To evaluate the associations between expression of miR-200b and RAB21, RAB23, RAB18 and RAB3B in breast cancer tissues, we further detected expression of miR-200b by ISH staining and expression of RAB21, RAB23, RAB18 and RAB3B protein by immunohistochemistry (IHC) staining in 10 pairs of tumor tissues and para-carcinoma tissues from breast cancer patients, who had developed distant metastasis after operation. Here, RAB21 is linked to breast cancer.