The deadliest form of skin cancer appears to cheat chemotherapy by disguising itself as a normal cell. Malignant melanoma kills more than 1,700 people each year in the UK, and can be hard to treat even with powerful anti-cancer medication. Researchers found melanoma cells can change shape, spread around the body, then remain dormant for years before developing a new tumour. The Marie Curie Research Institute study appears in Genes and Development.