IL1R1 and fibrosarcoma: We further performed ChIP-qPCR spanning +200 to –1000 bp of the IL1R1 TSS to confirm promoter TRF2 binding across multiple cell lines- HT1080 fibrosarcoma, MDAMB231 breast cancer, HEK293T immortalised kidney and MRC5 fibroblast cells (Figure 1—figure supplement 2H).