TSPO and neoplasm: Other roles indicated for TSPO include porphyrin transport (Verma et al., 1987; Wendler et al., 2003), cellular responses to stress (Batoko et al., 2015), inflammation (Maeda et al., 2007; Rupprecht et al., 2010), and tumor progression (Hardwick et al., 1999; Wu and Gallo 2013).