MPPE1 and lung carcinoma: Intratumoral DCs identified from human liver and lung cancers by scRNA-seq consisted of two major subpopulations corresponding to cDC1 and cDC2, a third “activated” cDC subpopulation marked by CCR7 and LAMP3, and a fourth pDC subpopulation derived from a distinct lineage (Figure 2; Lavin et al., 2017; Zhang et al., 2019; Zilionis et al., 2019).