MPPE1 and cancer: Restraining DNGR-1 activity may ensure that cDC1 activation leading to cross-priming occurs only in the presence of PAMPs (e.g., double stranded RNA within corpses of virally infected cells (Schulz et al, 2005)) or upon coincident detection of additional DAMPs such as may be present during pathology (e.g., cancer (Giampazolias et al, 2021)), and not under normal, non-pathological conditions.