Compared to other inducers of diverse classes of lytic cell death, a relatively low concentration of ErSO triggered comparable levels of LDH and HMGB1 release in MCF-7 human breast cancer cells and elicited exclusively necrotic cell death morphology (Fig. S1B-D), making ErSO an appropriate agent to use for exploring potential mediators of PMR and lytic cell death in breast cancer cells. Here, HMGB1 is linked to breast cancer.