CREB1 and breast cancer: MDA-MB-231_BH; CM + sulfasalazine vs CM + Sulfasalazine + KG501 p < 0.0001, CM + KG501 vs CM + Sulfasalazine + KG501 p < 0.0001) (Supplementary Fig. 4) .Taken together, our data demonstrate that IL1β stimulates Wnt-dependent CSC colony formation in the bone environment via an induction of NFκB and CREB signalling in breast cancer cells.