Precancerous cells, also called premalignant cells, are abnormal cells that have the potential to become cancerous, according to About.com. A precancerous cell is not destined to progress to cancer and can even return to a normal cell in the future.
Precancerous cells must undergo additional changes to progress to cancer, and there are degrees to the dysplasia of a precancerous cell. Cells with mild dysplasia are only slightly abnormal and have a low risk of becoming cancerous. Cells with moderate dysplasia are moderately abnormal and have a higher risk of turning cancerous. Cells with severe dysplasia are severely abnormal, and these have the highest risk of becoming cancerous, according to About.com.