https://www.drpriyatiwari.com/services/tongue-cancer-specialist-delhi An uncontrolled growth and spread of body cells, is often known as "Cancer." Under a microscope, the black dotted cells known as nuclei are identified as cancer-cells. This identity is defined in comparison to healthy living cells that are small (black dots) with a wall-like perimeter surrounding them. The large black-dotted nuclei has no such wall.