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Cancer Notes What is cancer? Cancer is a group of more than 100 diseases that develop over time and involve abnormal growth of certain cells.

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Presentation on theme: "Cancer Notes What is cancer? Cancer is a group of more than 100 diseases that develop over time and involve abnormal growth of certain cells."— Presentation transcript:

1 Cancer Notes What is cancer? Cancer is a group of more than 100 diseases that develop over time and involve abnormal growth of certain cells. http://www.cancer.gov/cancertopics/und erstandingcancer/cancer/slide1 http://www.cancer.gov/cancertopics/und erstandingcancer/cancer/slide1 What is a tumor? A tumor is when cells accumulate where they are not supposed to be.

2 Tumor Types of tumors 1. Benign – usually localized and do not spread to other body parts, cause little harm and grow slowly 2. Malignant – cancer, life-threatening; starts at one place and spreads to other places where a secondary tumor is formed http://www.cancer.gov/cancertopics/understa ndingcancer/cancer/slide9 http://www.cancer.gov/cancertopics/understa ndingcancer/cancer/slide9

3 More terms Proto-oncogenes – genes that encourage cell division (controls mitosis) and become oncogenes when mutated http://www.cancer.gov/cancertopics/understa ndingcancer/cancer/slide43 http://www.cancer.gov/cancertopics/understa ndingcancer/cancer/slide43 Oncogenes–genes that cause cancer by stimulating excessive division; cause extra cells in inappropriate places http://www.cancer.gov/cancertopics/understa ndingcancer/cancer/slide44 http://www.cancer.gov/cancertopics/understa ndingcancer/cancer/slide44

4 Apoptosis What is this? Apoptosis is programmed cell death or cell suicide. Apoptosis is needed for proper development. examples: loss of tadpole tail formation of fingers & toes

5 P53 Protein 53 This usually acts as a tumor suppressor and shuts off cell growth and division of damaged cells. May send a cell to apoptosis. http://www.cancer.gov/cancertopics/under standingcancer/cancer/slide47

6 Cancer genes in humans 6 characteristics of oncogenes 1.Make proteins that initiate mitosis 2.Usually turned off 3.Cancer occurs when mistakenly turned on 4.Usually not inherited – are born with normal copies 5.Act as a dominant trait 6.May be expressed with RNA viruses

7 6 characteristics of Tumor suppressor genes 1.Make proteins that inhibit mitosis 2.Are usually turned on 3.Cause cancer when mistakenly turned off 4.Often have inherited predisposition – only 1 mutation is needed 5.Act as recessive trait 6. May be expressed with DNA viruses

8 Steps to tumor/cancer development 1.One cell has a mutation & starts to grow faster than other cells. 2.5 years later – hyperplasia (extra normal cells); 1 cell has 2 nd mutation http://www.cancer.gov/cancertopics/un derstandingcancer/cancer/slide19 http://www.cancer.gov/cancertopics/un derstandingcancer/cancer/slide19

9 Steps to tumor/cancer 3.5 years later – (10 yrs from start) dysplasia (extra cells with unusual shape); 1 cell has 3 rd mutation http://www.cancer.gov/cancertopics/understandi ngcancer/cancer/slide20 4. In 4-5 years (15 yrs from start) have cancer in-situ, or in one place; 1 cell has 4 th mutation http://www.cancer.gov/cancertopics/underst andingcancer/cancer/slide21 http://www.cancer.gov/cancertopics/underst andingcancer/cancer/slide21

10 Steps to tumor/cancer 5.Cells grow through basal membrane, enter bloodstream and metastasize, or spread to other parts of the body; about 20 yrs from the start http://www.cancer.gov/cancertopics/understandi ngcancer/cancer/slide8 6.Multiple mutations are involved. ttp://www.cancer.gov/cancertopics/understandin gcancer/cancer/slide49

11 Body’s Back-up Systems DNA repair system – body detects & corrects errors in DNA; if these fail, the error or mutation becomes a permanent feature in that cell http://www.cancer.gov/cancertopics/understandi ngcancer/cancer/slide48 Cell sent to apoptosis (cell suicide) if some essential part is damaged or its control system deregulated.

12 Body’s Back-up Systems Cells are limited in the number of times they can divide; telomeres at the ends of chromosomes shorten each time a chromosome replicates; when short enough the cell stops dividing. http://learn.genetics.utah.edu/content/be gin/traits/telomeres/http://learn.genetics.utah.edu/content/be gin/traits/telomeres/


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