Chromatin immunoprecipitations (ChIP) were performed as described (Stelloo et al. Oncogene 2018) For each ChIP, 7.5μg of XBP1s antibody or 5μg of RNA polII Ser2 antibody prebound to protein A beads were used. In brief, Nuclear lysates were incubated with 5ug of RNA polymerase Serine 2 phosphorylation antibody (Abcam, ab5095) and 50ul protein A beads. Immunoprecipitated DNA was processed for library preparation (Part# 0801-0303, KAPA biosystems kit). Libraries were prepared according to Illumina's instructions accompanying the DNA Sample Kit (Kapa Biosystems kit,KK8234).