1. Gene expression in Cancerous cells a. Mutation – sequence change in the bases of DNA b. In cancerous cells, mutations cause cells to lose control over mitosis i. Proto-oncogene – protein normally causes cells to divide, mutation causes protein to produce a higher rate of mitosis ii. Multiple changes can occur. 1. make the proto-oncogene to the oncogene (mutated version) 2. Could make copies of the same gene 3. Could cause chromosome rearrangement. iii. Tumor suppressor gene – protein normally inhibits cell division 4. If it becomes mutated, you produce a non-functional protein or quit producing it all together 5.
Can lead to excessive cell survival. iv. The oncogene sends constant divide signals and the tumor suppressor genes are not stopping division, so the buildup of these cells can cause a tumor c. Two types of tumors v. Benign – mass of essentially normal cells which stays at the site of origin 6. Could have almost a “tissue covering” 7. Typically don’t cause problems unless they get large vi. Malignant – mass of “cancerous” cells that displaces normal tissue growth 8. Has the ability to move and change location 2. Number of mutations d. Most cancers require more than one mutation to occur vii.
If division occurs faster, the cell doesn’t have the same amount of time to make sure everything is okay viii. Most cancers appear later in life because it takes some time for a cell to develop numerous mutations ix. Can cancer be inherited? 9. If inherit one mutation and the cancer requires four, you have a predisposition for that type of cancer 10. Higher likelihood, but not certain 3. Carcinogens- Any agent that contributes to the development of cancer e. 1761 – John Hill reported increased nasal cancers in men that used excessive tobacco snuff f.
1775 – Percival Pot reported skin cancers in scrotum of adolescent men who in youth worked as a chimney sweep g. 1915 – Specific chemical linked by Katsosaburo Yamagiwa, Used code tar to induce tumors on the ears of rabbits h. Severity and Intensity Severity and Intensity Ultraviolet radiation: causes breaks between A-T base pairs and creates T-T dimers Basal Cell Carcinoma Squamous Cell Carcinoma Melanoma Melanoma Instead of UV hitting the cell, it hits the melanoma of the cell, which increases its production to protect DNA during process such as tanning i.
Chemical carcinogens examples: smoke, red dye #2, asbestos— There are 49 carcinogens in tobacco smoke including: nitrosamine, formaldehyde, arsenic, nickel, cadmium and benzopyrene j. Viruses—did not transplant cells, just viruses that caused cancer x. Insertion of viral oncogene Produce viral oncogene protein or produce a protein that can influence adjacent genes. If the oncogene is viral, it continues to signal cell division, with is carcinogenic virus attached. xi. Inserts near a cellular proto-oncogene Cellular DNA under the control of the viral promoter 4. Normal Tissue k.
Epithelial Sheets: Polarized cells that rest on a basal lamina with an exposed surface 11. Chemically different 12. Organization top and bottom 13. Neighboring cells maintain connections with each other and the basal lamina. l. Connective tissue is extracellular matrix 14. Matrix components are produced inside the cell and secreted 15. Collagen fibers: Protein that provides strength 16. Collagen matrix bound to actin of the cytoskeleton, fibronectin, and integrin. 5. Changes in Cancerous Tissue m. Uncontrolled Cell Division n. Loss of cell specialization—don’t perform normal functions o.
Cancerous cells look different 17. Plasma membrane changes 18. Cells lose contact with neighbors 19. Abnormal nuclei 20. Abnormal shape p. Chromosomal Abnormalities—The faster replication occurs the more mistakes q. Invade normal tissue—Cancerous cells can move into the blood stream, and colonize a new site=metastasis Patterns of Metastasis 21. Follows the circulatory system 22. Similar tissues 23. Follow chemical signals 24. Adhesion molecules in blood vessels stuck in the capillary system Cancer tends to corrupt the surrounding environment 6.
Types of cancers—Almost every tissue has a known cancer r. Carcinomas: Originate in coverings of body or glandular tissue (skin, lining of intestines, breast, liver) s. Sarcomas: Arise in connective tissue (bone and muscle) t. Leukemias: Arise from the bone marrow or blood forming tissues u. Lymphomas: Arise in the immune system 7. Protecting Processes v. The body’s DNA repair enzymes 25. BUT sometimes mistakes are missed especially if the cells are rapidly dividing. w. The body’s immune system 26. The body recognizes cells by the proteins on the surface.
Identifies the cell as “self” 27. Proteins identified as foreign are attacked by immune cells. 28. Cancer cells can be considered “self” and therefore may not be attacked by the immune system. x. Limited lifespan of normal cells 29. Cells normally can only double 20-50 times before stopping. Lives marked by telomeres. 8. Cancer vs. Treatments—Everything that goes right in a normal cell goes wrong in a cancerous cell y. So many different types of cancer z. Cancer cells are still “self” cells {. The same mechanisms that are uncontrolled are necessary for normal cell development |.
Cancerous cells compete for same nutrients as normal tissue 9. Current Common Treatments for Cancer }. Surgical removal 30. Problems: Possible to leave some of the cancerous cells in the body that could travel ~. Radiation Therapy-Internal or External 31. Kills cell by attacking DNA 32. Hit with radiation energy causing mutations > death 33. Problems: Can cause death of healthy cells . Chemotherapy 34. Attempt to disrupt rapid cell division with chemicals 35. Problems: Not specific to cancer cells 10. Future Treatments-Ways to “hit” the cancer cells only .
Cut off the blood supply to the tumor. 36. Make the environment unfavorable 37. As tumors grow, they can stimulate the making of new capillaries to bring nutrients to the cancer cells=Angiogenesis. Block this=Block tumor growth. Doesn’t happen in normal cells . Targeted Cancer Therapies- Drugs or substances that block the growth and spread of cancer by hitting processes specifically involved in growth and progression. 38. Many are inhibitors of tyrosine kinases that are upregulated in cancerous cells. 39. Specific to cancer type (single type of cell) 40.
May be an antibody treatment that will bind to a receptor. 41. Cause some to undergo apoptosis (Only kills harmful cells). . Biological Response Modifiers- Use of the immune system to help fight the production of cancers 42. Prevent cancer movement 43. Boost killing power of immune cells 44. Block or reverse the process that changes pre-cancerous cell into cancerous one 45. Make cancer cells more recognizable. Differences in a cancerous cell from a normal cell – Membrane is ruffled and loses association There is an increase/decrease in the number of chromosomes Division is sped up It can move.