Lecture Note
Cancer: DNA Synthesis, Mitosis, and Meiosis
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University:
California State University, Northridge -
Course:
BIOL 100 | Introductory Biology Academic year:
2007
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Views:
419
Pages:
23
Author:
Detzemva1
Chapter 5
Cancer:
DNA Synthesis, Mitosis, and Meiosis What Is Cancer?
• Benign tumors do not invade surrounding tissue
• Malignant tumors invade surrounding structures:
– are cancer
• Properties of Cancer cells
– Promote Angiogenesis
– Loss of contact inhibition
– Loss of anchorage dependence
2 Properties of Cancer cells
• Angiogenesis
– growth of blood vessels caused by secretions from cancer
cells
• Increases the blood supply to cancer cells:
– more oxygen and nutrients
• Cancer cells can divide more
• Tumors develop, sometimes filling entire organs
3 Properties of Cancer cells
• Contact inhibition
– in normal cells prevents them from dividing all the time
– Divisions would force the new cells to pile up on each
other
4 Properties of
Cancer Cells:
Lack of
contact inhibition
Normal skin cells
Grow in monolayer
Skin cancer cells
Do not grow in monolayer
Pile up on each other
5 Properties of Cancer cells
• Anchorage dependence in normal cells keeps the
cells in place
6 Multiple Hit Model of Cell Transformation
to Cancer
• Many mutations, or hits, in a cell are required for it
to become malignant or cancer
• Multiple hit model describes the process of cancer
development from a normal cell
• Mutations can be inherited and/or can stem from
environmental exposures
7 Most cancers result from exposures to mutagens
•
•
If one sib or twin gets cancer, other usually does not
Populations that migrate – profile of cancer becomes more like
people indigenous to new location
8 Multiple Hit Model of Cell Transformation
to Cancer
9 The Multiple
Hit Model for
Colon Cancer
10 5.5 Cancer Detection and Treatment
• Earlier detection and treatment of cancer greatly increase
the odds of survival
• Knowing the warning signs of cancer is important to health
• Cancer screenings extremely important
• Self exams can catch early tumors both benign and
malignant
11 Cancer Detection
12 Cancer Detection Methods
• Blood tests for
• High blood cell counts
– May indicate a leukemia or lymphoma
• High protein concentration
– May indicate a tumor is making lots of protein
• Prostate cancer PSA
• Ovarian cancer CA125
• Biopsy
– When a tumor is found and cancer is suspected
– the surgical removal of cells, tissue, or fluid for analysis
• Under a microscope:
– benign tumors appear orderly and resemble other normal cells
– Malignant tumors do not resemble normal tissue
13 Cancer Detection Methods: Biopsy
14 Treatment Methods
• When possible, surgeons remove tumors with a
laparoscope through small incisions
– generally lead to quicker, easier recoveries
• 1 to 2 weeks
– are possible only when growths are small
• Others are surgically removed and require much
longer recovery time
• 6-8 weeks
• Continued monitoring and other treatments may
come after surgery
15 Treatment Methods: Chemotherapy
• Chemotherapy is used for cancer that cannot be surgically
removed or that has metastasized
– Any Chemical or drug that kills cancer cells is considered
chemotherapy
• Classical chemotherapy kills all dividing cells and is usually
injected into the bloodstream
• Combinations of chemical agents are usually used since
cancer cells can become resistant
•
• Adverse effects on chemotherapy patients during treatment
–
–
–
–
Hair loss
Nausea
Immunosuppression
fatigue
16 Treatment Methods: Chemotherapy
• Newer chemotherapy drugs target just cancer cells
– Not all dividing cells
• Successful tumor specific drugs
– Her2/neu = Herceptin for Breast Cancer
– Bcr/abl = Gleevec for CML
– CD20 = Rutuxan for Non Hodgkin Lymphoma (NHL)
• Block necessary component for tumor cell growth
• Does not harm normal cells
• Very few if any side effects
• Activate our own immune system to specifically kill tumor
cells
17 Treatment Methods: Radiation
• Radiation therapy
– High energy radioactive particles damage DNA and kill
cells
– Highly focused on tumor area
• Radiation therapy is can be administered with or
without chemotherapy
• A patient is in remission if the patient is no longer
suffering negative impacts from cancer after a given
period
18 Essay 5.1 Cancer Risk Factors
Known risk factors are linked to particular cancers…
19 Essay 5.1 Cancer Risk Factors
Known risk factors are linked to particular cancers…
20 Essay 5.1 Cancer Risk Factors
Known risk factors are linked to particular cancers…
21 Essay 5.1 Cancer Risk Factors
Known risk factors are linked to particular cancers…
22 Essay 5.1 Cancer Risk Factors
Known risk factors are linked to particular cancers…
23
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