CD74 and cancer: The protein CD74 is expressed on antigen-presenting cells and reports showed that CD74 expression serves as a prognostic factor in many cancers (Ekmekcioglu et al., 2016; Otterstrom et al., 2014; Ruvolo et al., 2019; Zeiner et al., 2015; Zeiner et al., 2018; Zhang et al., 2014).