1. What is Cancer? A general term for a large group of diseases characterized by uncontrolled growth of abnormal cells.

2. Cellular Growth Neoplasm: Any abnormal growth. May be benign or malignant, but the term is generally used to describe cancer. Hypertrophy: Enlargement of a tissue or organ because of the enlargement of individual cells. Hyperplasia: Increase in the size of a tissue due to the increase in the absolute number of cells.

3. Cell Differentiation (quality) Metaplasia: A uniform and predictable change in cell type that is predictable, physiological and often reversible. Dysplasia: An abnormal degree of variation, size, shape and appearance occurring in cells. Often non-physiological and irreversible.

4. Differences in Cancer cells and Normal cells Structural: Chromosomal abnormalities Irregular shape and size

5. Differences in Cancer cells and Normal cells Functional: Loss of production of specialized proteins Modified contact inhibition Altered surface antigens Very high metabolic requirements Release of angioplastic substances to stimulate growth

6. Benign Tumors Characteristics: Expand by simple local growth Plateau Become encapsulated Smooth borders Effect on Host: Compression Constriction Ulceration Hypersection

7. Malignant Tumors (Carcinoma-epithelial; Sarcoma-bone, muscle, connective) Characteristics: Rapid growth Loss of specialization Neither cohesive or encapsulated *Patterns of metastasis are usually predictable via blood vessels or lymph channels

8. Malignant Tumors Effects on Host: Effects of benign tumors Weight loss Wasting of tissue Anemia Electrolyte & fluid imbalances Malnutrition

9. How do cells become malignant? The process appears to occur as multi-stage process. INITIATION: Conversion of cells to those with neoplastic potential (DNA changes as a result of exposures to carcinogens) PROMOTION: Some form of chronic irritation that accelerates the rate of growth of already abnormal cells

11. How do cells become malignant? CARCINOGENIC SUBSTANCES (MUTAGENS): May influence cells to become malignant in a number of ways: Change the structure of cellular DNA (mutation) Add genetic information (viruses may act in this manner) Depress oncogenes and turn on existing genetic codes.