- a complex multistage process of abnormal cell growth and differentiation that can lead to cancer Usually at least two stages and toxicants are involved: initiation in which a normal cell undergoes irreversible changes and promotion in which the initiated cells are stimulated to progress to cancer
The potential for development of cancer in a living individual A cancer is a malignant tumor resulting from a change in the normal growth and development of cells (Cancerous tumors have the tendency to invade surrounding tissue and spread to other sites in the body )