Regulating the Cell Cycle the cell cycle has a built-in genetic signals to tell cells when to start and stop dividing –proto-onco genes – genes that encourage cell division –tumor suppressor genes – genes that inhibit cell division

Cancer a disorder in which some cells lose the ability to control their own growth these cells divide uncontrollably resulting in a tumor –tumor – an abnormal growth of tissue, not necessarily cancerous

Cancer involves a loss of control over the cycle, malfunction of the “brakes” the malfunction is caused by a mutation –Mutation – a change in a cell’s genes (DNA) –Oncogenes – mutated proto-onco genes that stimulate excessive division

Cancer when cancer cells break loose from a tumor they can spread to other parts of the body, thus spreading the cancer –Metastasis – spreading of cancer from one area of the body to another uncontrolled division can compromise the function of an organism and ultimately may cause death

Cancer and metastasis Cancer

Statistics (from the National Institutes of Health) On average, in the US: –men have a 1 in 2 lifetime risk –women have a 1 in 3 lifetime risk Cancer is the second leading cause of death in the US, after heart disease. The National Cancer Institute estimates that approximately 8 million American alive today have a history of cancer

Risk Factors Many Americans have a higher than average chance of developing cancer Risk Factors can be broken into two categories: –Factors that you have control over smoking, diet, environmental –Factors that you have no control over genetics (family history), environmental

Regulating the Cell Cycle the cell cycle has a built-in genetic signals to tell cells when to start and stop dividing –proto-onco genes – genes that encourage cell division –tumor suppressor genes – genes that inhibit cell division

Stages of Cancer Stage 0 – small clump of pre- cancerous cells Stage 1 – localized tumor that is small and has not metastasized (spread) into nearby lymph nodes

Stages of Cancer Stage 2 – larger tumor that has metastasized (spread) to nearby lymph nodes Stage 3 – even larger tumor that has metastasized (spread) to more lymph nodes

Stages of Cancer Stage 4 – cancer that has metastasized (spread) into other areas of the body using lymph or blood vessels forming new tumors

4 Major Treatment Options 1.Surgery – removal of the affected tissue 2.Radiation – exposing the affected area to ionizing radiation

4 Major Treatment Options 3.Chemotherapy – treatment using chemicals that harm rapidly dividing cells 4.Immunotherapy – enhancing the body’s immune system to help fight cancer

Other Resources Pg in your textbook National Institutes of Health –(see “Related Links” sections also…) National Cancer Institute