PTEN and melanoma: The activation of BRN2 expression in a specific subset of melanoma cells in response to all three major signaling pathways (MAPK, PI3K/PTEN, and β-catenin) linked to melanoma initiation (early proliferation and bypass/escape senescence) and progression (including late proliferation and metastatic dissemmination) suggests that Brn2 is likely to have a critical role in disease progression26.