 Abnormal growth of cells = a tumor  BENIGN = tumor that lacks the ability to spread to another area/ tissues  MALIGNANT = tumor that spreads to other tissues  All tumors are a result of mutations that occur during the mitotic process.

 METASTASIS : process where a tumor spreads from one area to another  Cancers are classified according to the type of tissue from which they arise  The chance of occurrence is related to the rate of cell division

1. Cancer cells can divide without appropriate external signals. This is analogous to a car moving without having pressure applied to the gas pedal. An example would be the growth of a breast cancer cell without the need for estrogen, a normal growth factor. Some breast cancer cells actually lose the ability to respond to estrogen by turning off expression of the receptor for estrogen within the cell. These cells can still reproduce by bypassing the need for the external growth signal.

2. Cancer cells do not exhibit contact inhibition. While most cells can tell if they are being 'crowded' by nearby cells, cancer cells no longer respond to this stop signal. The continued growth leads to the piling up of the cells and the formation of a tumor mass. 3. Cancer cells can divide without receiving the 'all clear' signal. While normal cells will stop division in the presence of genetic (DNA) damage, cancer cells will continue to divide. The results of this are 'daughter' cells that contain abnormal DNA or even abnormal numbers of chromosomes. These mutant cells are even more abnormal than the 'parent' cell. In this manner, cancer cells can evolve to become progressively more abnormal.

4. Continued cell division leads to the formation of tumors. 5. The genetic instability that results from the faulty division contributes to the drug resistance seen in many cancers. 6. Mutations in specific genes can alter the behavior of cells in a manner that leads to increased tumor growth or development. 7. VIDEO VIDEO

1. CARCINOMAS : start in epithelium = most common type of cancer (90%) – skin, mouth, lung, breast, stomach, colon, prostate, uterus (usually spread by lymph system) 2. SARCOMAS : arise in the connective tissue – found in muscle, bone, & cartilage- usually spread by blood. 3. LEUKEMIAS : cancers of the blood 4. MELANOMAS – start in birthmarks or moles 5. GLIOMAS – start in connective tissue of brain and spinal cord 6. LYMPHOMAS – cancers of the reticular connective tissue- found in lymph tissue

1. Cancer often has no specific symptoms, so it is important that people limit their risk factors and undergo appropriate cancer screening. 2. Most cancer screening is specific to certain age groups and your primary-care doctor will know what screening to perform depending on your age. 3. People with risk factors for cancer : smokers, heavy alcohol use, high sun exposure, genetics 4. However you should see a doctor if you experience any of the following:

a) Persistent cough, blood-tinged saliva, or hoarseness b) A change in bowel habits c) Unexplained anemia d) Lumps in the tissue e) A change in urination or blood in the urine f) Unexpected weight loss, night sweats, or fever g) Unusual bleeding or discharge h) Headaches (severe and do not stop with over the counter pain meds)