POU4F1 and melanoma: On transcript level, Bcl-2 and Bcl-xL were reported to be transcriptionally upregulated by Brn3a (Smith et al, 1998, 2001), however, in melanoma, Bcl-xL mRNA was not altered upon Brn3a inhibition and Bcl-2 mRNA levels were indirectly regulated by activated p53 (see below) as evidenced by co-inhibition studies (Supporting Information Fig S2C).