2.  Made of certain proteins.  Directs the timing and sequence of events in the cell cycle.  If something goes wrong, Cells lose control of cell cycle

3.  A disease caused by a disruption to the cell cycle leading to uncontrolled cell division.

4.  Masses of tissue made of cells.  Benign Tumor  Abnormal masses of essentially normal cells.  Stay at original site of growth.  Malignant Tumors  Mass of cancerous cells  Displace normal tissue as it grows.  Can Spread to surrounding tissue. Metastasis

5.  Environmental: Caused from the surroundings  Example= cigarette smoke, pollution, UV (sun)  Genetic Factor: mutation found in the genes.  Example= BRCA1 or BRCA2 gene

6.  Radiation Therapy and Chemotherapy  Both disrupt cell division.