CCL5 and carcinoma: As CCL5 is able to mediate cross-talk between the tumour cells and the tumour microenvironment40, it may be possible that CCL5 modulates macrophage polarization in our study, as we have shown that CCL5 is the major chemokine secreted by 4T1 carcinoma cells and is able to induce macrophage polarization to an alternatively activated subtype.