CCR4 and breast cancer: Studies in humans and mice have shown that Tregs express a wide range of chemokine receptors that may facilitate intratumoral homing, of which CCR2, CCR4, CCR5, CCR8, CXCR3, and CXCR6 have been associated with breast cancer (Plitas et al. 2016, Yano et al. 2019).