IL6 and neoplasm: To determine whether IL6 blockade (tocilizumab) would influence sensitivity to HT, FulvR bone metastases (FulvR-Bone-Met) were isolated, passaged and re-injected into new cohorts of mice: once tumours reached ∼1 cm, mice were randomized to receive fulvestrant with or without tocilizumab (Fig. 2a: Fulv, Fulv-Toci).