A movie “Do Not Disturb” made people remember the disease “melanoma”, and many patients with “moles” came to the dermatology clinic at once. So what is “melanoma”? What is a “mole”? A “mole” is a benign skin tumor consisting of clusters of melanocytes and surrounding tissue that can appear pink, yellowish-brown, brown or close to normal skin color. Melanomas are formed by the malignant transformation of melanocytes, which are out-of-control melanocytes that have a tendency to metastasize and are life-threatening. ”Moles” can be divided into junctional nevi, mixed nevi, and intradermal nevi. Melanoma is often formed by the malignant transformation of the first two, while the latter is usually not malignant. ”Moles are usually formed as a reaction to sunlight. 1% of moles are present at birth and may grow as people grow and even develop hair. Most common moles usually do not develop into melanoma, but when the original mole changes in size, shape, color and texture, or when the following conditions exist, high alert is needed, such as congenital giant moles, abnormal developmental moles, multiple moles (more than 50), moles at the end of the limbs, moles or hyperpigmentation in the digestive and genitourinary tracts, and moles exposed to sunlight for a long time. Currently, oncologists have summarized the ABCDE rule to help people remember and recognize the changes of moles: A: Asymmetry: One half of the mole looks asymmetrical with the other half. B: Border irregularity: The edges are irregular or have cut marks or jagged teeth, unlike normal pigmented moles that have smooth round or oval outlines. C: Color Variation: Normal moles are often monochromatic, while melanoma has different colors such as brown, brown, brown-black, blue, pink, black, and white. D: Diameter: A mole larger than 5mm in diameter or significantly larger in a short period of time requires caution. Any mole larger than 1cm should be biopsied for evaluation. E: Elevation: Any hyperpigmented lesion with rapid elevation or surface unevenness should be examined immediately. Please seek prompt medical attention when any of the above occurs.