AFP and cancer: In fact, similar to ECs, cancer cells are also pluripotent because xenograft tumors formed by cancer cells show expression of markers of tissue/cell types derived from all three germ layers, for example, SOX1-expressing cells representing cells with neural stemness and derived from ectoderm, ACTA2-expressing cells derived from mesoderm, and AFP-expressing cells derived from endoderm (Xu et al., 2021; Cao, 2022; Zhang et al., 2022).