Specifically, what was relevant was the ability of RARβ and RARγ coactivation to lead to a rescued neuronal phenotype at the end of 10 days of cell differentiation in P19 embryonic carcinoma cells, while the individual activation of these receptors with their synthetic agonists (BMS641 and BMS961, respectively) did not do so. This evidence concerns the gene RARB and embryonal carcinoma.