HSF1 and cancer: Our initial in vitro findings in MEFs (Fig. 1), together with our MxIF analysis of HSF1 localization and activation in the colon (Fig. 6), strongly indicate that, while HSF1 in cancer cells is important for tumor growth, and HSF1 in immune cells may contribute as well (Supplementary Fig. 4e–h), HSF1 in fibroblasts is a major player in driving the ECM rearrangements observed in AOM-DSS-treated mice.