F2RL3 and breast cancer: 2015). We also showed that PAR4 activation leads to urothelial MIF release that likely acts on MIF receptors to induce urothelial HMGB1 release (Kouzoukas et al. 2016). MIF‐induced HMGB1 release is in agreement with a recent in vitro study showed that MIF promotes HMGB1 release in breast cancer cells (Lv et al. 2016). We also demonstrated that intravesical dsHMGB1 (but not the thiol form) elicited mechanical hypersensitivity through activation of toll‐like receptor 4 (TLR4) receptors (Ma et al. 2017).