ABSTRACT
A cancer stem cell is an abnormal cell that divides in an uncontrolled manner, giving rise to other abnormal cells that collectively form a tumor. For a normal cell to transform into an abnormal cell, there are two minimal capabilities it needs to have or acquire. Cancer cells need an abundance of energy and raw materials to divide. With the arrival of appropriate signals, blood vessel epithelial cells commence division to form new branches that grow outwards and extend into tumors. Invasion occurs when tumor cells breach the barrier that separates them from a different tissue type and grow into its space. When a tumor acquires the ability to invade surrounding tissues it becomes a cancer, and takes on a new menace. Treatment regimens that inflict damage on the deoxyribose nucleic acid (DNA) of tumor cells may by chance promote the development of resistant strains.
