Then, aiming to assess whether any of the tumour clusters have shifted from a differentiated melanocytic state to a more undifferentiated or mesenchymal-like/invasive state34, we compared the expression levels of melanocytic (TYR, MLANA, DCT and MITF) and mesenchymal (ZEB1, VIM, FN1 and AXL) marker genes in the tumour clusters. The gene discussed is AXL; the disease is neoplasm.