PDIA4 and neoplasm: We also measured activation of ER stress in SAHA-treated Tsc1iΔEC tumour cells, as increased ROS has been reported to trigger downstream pathways leading to ER stress pathway activation.44 RT-qPCR showed increased levels of Bip and Bim, but not ERp72, which are associated with ER stress signalling (Supplementary Fig. S4).