AR and melanoma: Cyp26b1 is involved in retinoic acid metabolism and has a role in neural crest-derived tissue development.22 Meiosis-related genes are often upregulated in melanoma cells that are particularly prone to so-called ‘meiomitosis', describing the partial expression of meiosis machinery in mitotic cells.23 Taken together, the expression profile provides evidence for melanocyte dedifferentiation, which is a typical feature of invasive melanoma cells,24, 25, 26 upon long-term N-RAS61K activation and reveals the expression of stem-like and meiosis-associated genes in N-RAS61K-AR cells.