1. Cancer Deregulation of cell cycle Loss of control of mitosis Result of mutation Over 200 types of cancer exists (Number of cancer cases will double by 2050, as an increasing proportion of U.S. population reaches older ages)

2. United States Cancer Death Rates

5. Characteristics of Cancer (no matter what type) Uncontrolled cell growth- most significant characteristic of all cancer cells Loss of cell differentiation ( specialization) – Ex. Skin cell no longer produces another skin cell Invasion of normal tissues, occupying space that should contain normal cells Metastasis or spread to multiple sites

6. Stages of Cancer 1.Initiation (Stage I) 2.Promotion (Stage II) 1.Progression (Stage III)

7. Initiation of Cancer (Transformation) Series of gene mutations damages DNA Proto-oncogenes change to oncogenes (“on” switches for tumors or masses) Caused by: combination of mutations – Allow tumor (abnormal cells) to begin Initiation does not directly result in cancer, it results in a precancerous cell. Heredity acts only as an initiator, not a promoter

8. Promotion of Cancer Cells are stimulated to grow & divide when they normally would not. Growth is gradual Carcinogens – agents that both initiate & promote cancer – Viruses – Chemicals – Radiation Benign cells – Masses of partially transformed cells, confined & encapsulated – Cells exhibit dysplasia-growth patterns char. of cancer cells

9. Normal Cells Dysplastic Cells

10. Progression of Cancer Cells become less differentiated Cells invade other tissue Move to other areas of the body Called malignant cells