Cancer cells differentiate from normal cells by their ability to:
· Continue multiplying
§ Normal cells cease proliferation when enough cells are present. Cancer cells, on the other hand, contain mutated genes. Changes in a cell’s genes causes miscomprehension of instructions, and therefore abnormal proliferation. On average, it takes about six mutations before a normal cell turns into a cancer cell.
o Normal cells mature and specialize into differentiated cells. Cancer cells, however, remain undifferentiated because they reproduce rapidly before the cell have a chance to mature. The grade of cancer normally corresponds to the degree of cell maturity. With 1 being the least aggressive and 3 being the most aggressive.
o Unlike normal cells, cancer cells do not respond to signals from other nearby cells. Hence, they are unable to know when they’ve reached their boundaries and should stop growing.
· Avoid apoptosis
o When cells get damaged or old, they either get repaired or undergo apoptosis (cell death). Cancer cells however, are missing or having an inactive or abnormal P53 protein which advises them on which to do. They are, therefore, allowed to multiply and reproduce as per normal.
· Evade the immune system
o Cancer cells are able to evade death either by escaping detection or through secretion of certain chemicals that inactivate immune cells that come to the scene. Normal cells however, are susceptible to the detection of the immune system and can be removed.
o Normal cells create cell-cell contact through the secretion of a sticky substance, Claudin-5, made of proteins on the surface of their cells. These proteins make contact with similar proteins on other cells in order to stick together as a group. Cancer cells, however, can “float away” to locations nearby or (through the bloodstream or lymphatic system) to distant regions in the body, due to their inability to make these sticky substances. There, they begin to grow and form new tumors far from the original tumor.
· Influence normal cells
o Cancer cells are able to signal nearby normal cells through angiogenic factors to encourage formation of blood vessels thereby supplying tumors with oxygen and nutrients, which they need to grow.