For ChIP in the tumours and metastases, the frozen sample was cut into smaller pieces and thawed in 1% (final concentration) formaldehyde for 20 minutes at room temperature. The reaction was quenched by adding 0.1 volume of 2M glycine for 10 minutes. The sample was disaggregated by Dounce homogenisation and processed according to standard ChIP procedures (Schmidt D et al, Methods, doi:S1046-2023(09)00047-4 [pii]). The DNA was subsequently amplified as previously described (Schmidt D et al, Methods, doi:S1046-2023(09)00047-4 [pii]). For the malignantpericardial effusion, epithelial cells were first enriched using Dynabeads conjugated with Epcam. For ChIPs from cell line material, proliferating cells were cross-linked and processed for ChIP as previously described (Schmidt D et al, Methods, doi:S1046-2023(09)00047-4 [pii]). For the TAM-R cells, ER ChIP-seq was performed on cells grown in DMEM containing 10% FBS and 10 nM tamoxifen for 24 hours. For the cocktail experiments, cells weretreated with 100 ng/ml IGF-1, 100 ng/ml EGF, 1 ng/ml TNF-alpha and 10 ng/ml IL-6 for 90 minutes.