A stands for assymetry, one half of the mole does not resemble the other half. B stands for irregular irregular border or edge.
C stands for color.
The color within the mole includes shades of brown, red tan and white. There is not a uniform color to the mole. D stands for diameter. In genral, malignant moles are usually larger than six millimeters or the end of a pencil eraser. If a mole itches, bleeds, or changes in size, shape or color, see a doctor.