MCU and neoplasm: A number of proteins contribute to the channel complex (Raffaello et al, 2013; Sancak et al, 2013; Foskett & Philipson, 2015) and others regulate its activity (Perocchi et al, 2010; Plovanich et al, 2013; Patron et al, 2014), but little is known about the role of MCU‐dependent mitochondrial Ca2+ homeostasis in tumor progression.