While chemokine receptors belong to the G protein-coupled receptor superfamily localized on the cell membrane, some of them, including CCR1, 3 and 5, are known to internalize to the cytoplasm following interactions with its ligands [20,21,22], and the cytoplasmic immunoreactivity of CCR1, 3 and 5 may suggest that these receptors are “active” in breast cancer tissues. Here, CCR1 is linked to breast cancer.