We have first found that zygotes from AhR−/− mice have basal overexpression of well-known pluripotency factors Oct4, Nanog, and Sox2, in agreement with our previous studies reporting that AhR-null mice have an increased ability to regenerate lung (Laiosa et al., 2015) and liver (Wang et al., 2016), and a higher potential to sustain undifferentiation of human embryonic carcinoma cells (Roman et al., 2018). This evidence concerns the gene SOX2 and embryonal carcinoma.