Cancer is caused by the accumulation of pathogenic alterations of the genome and epigenome that result in permanent changes that disrupt cellular homeostasis. The genes that become corrupted in this process vary among different tumour types, reflecting specific vulnerabilities and dependencies of the cell from which the cancer originated. This also applies to 'melanoma', a cancer that constitutes not one, but multiple diseases that can be separated based on their cell of origin, aetiology, clinical appearance and course, and response to treatment. In this article, we review the current classification of melanoma within distinct evolutionary pathways and the associated genetic alterations. In addition, we review the application of molecular diagnostics to the diagnosis of melanocytic tumours in the context of histopathological assessment.
© 2021 British Association of Dermatologists.