Cardiomyocyte differentiation is regulated by signalling pathways, including wingless and integrase (WNT) and Hdac1. Liu et al. demonstrated that Hdac1 influences the WNT pathway, using P19CL6 (P19CL6 cells are a subclone of the P19 embryonal carcinoma cells). This evidence concerns the gene HDAC1 and embryonal carcinoma.