At least one study has shown that Sig1R antagonists cause shrinkage of cancer cells [17] and Sig1R has been proposed to promote apoptosis resistance in cancer by exerting a tonic clamp of volume‐regulated K+ and Cl− channels, which prevents apoptotic volume decrease without affecting regulatory volume decrease; the latter being required for cell division [45, 46]. Here, SIGMAR1 is linked to cancer.