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Title: PowerLecture: Chapter 23


1
PowerLectureChapter 23
  • Genes and
  • Disease Cancer

2
Learning Objectives
  • Understand the relationship between cancer and
    cellular genetic controls.
  • Know the steps in cancer development.
  • List the environmental factors that influence
    cancer development.
  • Describe the relationship between lifestyle and
    cancer.
  • Describe some of the characteristics of more
    well-known cancers.

3
Impacts/Issues
  • Between You
  • and Eternity

4
Between You and Eternity
  • Cancer affects one in three people in the U.S.
    and kills one in four each year more than
    200,000 women are diagnosed with breast cancer
    alone.
  • Some women carry the BRCA1 or BRCA2 gene, which
    increases the risk of developing breast cancer.
  • Some women with elevated risk for breast cancer
    opt for preventive mastectomy.
  • Diagnosed early, most cancers are treatable, and
    many curable.

5
Video Preventing Cancer Surgically
  • This video clip is available in CNN Today Videos
    for Anatomy and Physiology, 2003, Volume VII.
    Instructors, contact your local sales
    representative to order this volume, while
    supplies last.

6
Useful References for Impacts/Issues
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • Genome News Network Breast Cancer Susceptibility
    Genes Overstating the Risk?
  • InfoTrac Monster Tumors Show Scientific
    Potential in War against Cancer. Elizabeth
    Svoboda. The New York Times, June 6, 2006.

7
How Would You Vote?
  • To conduct an instant in-class survey using a
    classroom response system, access JoinIn Clicker
    Content from the PowerLecture main menu.
  • Would you support legislation requiring insurers
    to pay for the removal of a breast that is only
    at risk for developing cancer?
  • a. Yes, they should be required to pay at least
    in proportion to a woman's chances for developing
    cancer.
  • b. No, they should pay for annual exams, but not
    for surgery unless cancer is actually detected.

8
Useful References for How Would You Vote?
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • InfoTrac Breast Removal The Latest in Cancer
    Prevention. HealthFacts, Feb. 1999.
  • InfoTrac Is a 0.2 Chance of Death from Breast
    Cancer Worth a Bilateral Prophylactic Mastectomy?
    Contemporary OB/GYN, June 2005.
  • American Cancer Society Insurance May Not Cover
    Preventive Surgery for High-Risk Women

9
Section 1
  • Cancer Cell
  • Controls Go Awry

10
Cancer Cell Controls Go Awry
  • Some tumors are cancer, others are not.
  • Overgrowth of cells in a tissue (hyperplasia)
    results in the formation of a defined mass called
    a tumor, or neoplasm.

Figure 23.2
11
Cancer Cell Controls Go Awry
  • Benign tumors are often enclosed in a capsule of
    connective tissue.
  • The cells are organized in orderly array.
  • The cells grow slowly and are well
    differentiated.
  • Because they do not affect surrounding tissue
    (there are exceptions), they usually are not
    considered a threat to health.

12
Fig 23.1, p.428
capsule
13
Cancer Cell Controls Go Awry
  • Dysplasia is an abnormal change in the sizes,
    shapes, and organization of cells in a tissue.
  • It is often a precursor to cancer.
  • Microscopically, the edges of the tumor look
    ragged and the cells are clumped.
  • Functionally the cells have many characteristics
    that alter their behavior from that of normal
    cells.

14
Cancer Cell Controls Go Awry
  • Cancer cells have abnormal structure.
  • A cancer cell has a large nucleus, less
    cytoplasm, and is poorly differentiated.
  • The cytoskeleton shrinks and becomes
    disorganized proteins of the plasma membrane
    also become altered.
  • Cellular division of transformed cells results in
    cancerous daughter cells.

15
Cancer Cell Controls Go Awry
  • Cancer cells lack normal controls over cell
    division.
  • In a cancerous tumor, more cells are dividing
    than dying, so growth continues unaffected by the
    usual contact inhibition provided by crowding.
  • Cancer cells lack strong cell-to-cell junctions
    and so tend to move about (metastasis) and become
    malignant.

16
Fig 23.3, p.429
Cancer cells break away from their home tissue.
a
The metastasizing cells become attached to the
wall of a blood vessel or lymph vessel. They
secrete digestive enzymes into it. Then they
cross the wall at the breach.
b
Cancer cells creep or tumble along inside blood
vessels, then leave the bloodstream the same way
they got in. They start new tumors in new
tissues.
c
17
Cancer Cell Controls Go Awry
  • Some cancer cells produce HCG (human chorionic
    gonadotropin), which can be detected in blood and
    which signals cancer somewhere in the body
    cancer cells also produce angiogenin, which
    encourages new blood vessel development.

18
Animation Cancer and Metastasis
CLICKTO PLAY
19
Animation Characteristics of Cancer
CLICKTO PLAY
20
Video Fibroid Tumors
  • This video clip is available in CNN Today Videos
    for Anatomy and Physiology, 2004, Volume VIII.
    Instructors, contact your local sales
    representative to order this volume, while
    supplies last.

21
Useful References for Section 1
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • InfoTrac Gene Signature Helps Predict Melanoma
    Outcome. Diana Mahoney. Internal Medicine News,
    Mar. 1, 2006.

22
Section 2
  • The Genetic Triggers
  • for Cancer

23
The Genetic Triggers for Cancer
  • Cancer develops in a multistep process.
  • The transformation of a normal cell into a
    cancerous one is called carcinogenesis.
  • Cancer develops through a series of changes that
    upset normal controls over cell division.
  • Oncogenes induce cancer when tumor suppressor
    genes are mutated.
  • Proto-oncogenes are normal genes that regulate
    cell growth and development.

24
Fig 23.4, p.430
POSSIBLE TRIGGERS
virus
chemical carcinogens
normal cell
radiation
heredity
mutation in proto-oncogenes and tumor suppressor
genes remove normal growth controls
abnormal cell
immune system activated (cytotoxic T cells and NK
cells)
immune system breakdown
abnormal cell proliferates
abnormal cell destroyed
tumor
tumor cells break away metastasis to other parts
of body
25
Fig 23.4, p.430
POSSIBLE TRIGGERS
virus
chemical carcinogens
radiation
heredity
mutation in proto-oncogenes and tumor suppressor
genes remove normal growth controls
abnormal cell destroyed
tumor cells break away metastasis to other parts
of body
Stepped Art
26
The Genetic Triggers for Cancer
  • Oncogenes are modified from proto-oncogenes they
    code for altered proteins that remove the
    controls over cellular division.
  • Cancer cannot be caused by oncogenes alone but
    requires the absence or mutation of tumor
    suppressor genes.
  • For example, retinoblastoma is normally
    suppressed by at least one gene, but if this gene
    is altered, the suppression is removed and cancer
    develops.
  • BRCA1 and BRCA2 are also tumor suppressor genes
    whose disruption can lead to breast cancer.

27
Fig 23.5, p.431
BRCA 2
BRCA 1
Chromosome 13
Chromosome 17
28
The Genetic Triggers for Cancer
  • The p53 gene codes for a regulatory protein that
    turns on proto-oncogenes that stop cell division
    at the right time its alteration removes this
    inhibition and allows cells to divide unchecked.
  • An oncogene may mutate in a way that triggers
    expression.
  • Translocation may move an oncogene away from a
    regulatory nucleotide sequence that normally
    prevents its expression.
  • New genetic material may be introduced into a
    cell (as by a virus) and disrupt controls.

29
The Genetic Triggers for Cancer
  • There also are other routes to cancer.
  • Inherited susceptibility to cancer.
  • If a mutation occurs in a germ cell and it
    removes controls over a proto-oncogene, the
    defect can be passed on to offspring.
  • Most instances of inherited cancer susceptibility
    are complicated by the fact that several genes
    are probably involved.
  • Viruses.
  • Viruses can become inserted into host cell DNA,
    possibly altering the functioning of
    proto-oncogenes.
  • Viruses can also carry oncogenes and insert them
    into host cell DNA.

30
The Genetic Triggers for Cancer
  • Chemical carcinogens.
  • Carcinogens are chemicals that can damage DNA,
    resulting in subsequent mutations.
  • Some of the chemicals that cause cancer are
    by-products of an industrialized society, such as
    asbestos, vinyl chloride, and benzene
    hydrocarbons in cigarette smoke and fireplace
    soot and substances in dyes and pesticides.
  • Natural carcinogens include aflatoxin, produced
    by a fungus that grows on peanuts.
  • Some chemicals may be pre-carcinogens that
    cause changes only after they have been altered
    by metabolic activity of the cell.

31
The Genetic Triggers for Cancer
  • Radiation.
  • Radiation can damage DNA.
  • Sources include UV radiation from sunlight and
    tanning lamps, X rays, cosmic rays, radon gas,
    and nuclear reactors sun exposure is probably
    the greatest risk factor.
  • Breakdowns in immunity.
  • A healthy immune system regularly detects and
    destroys cancer cells by means of cytotoxic T
    cells.
  • The protective function of the immune system can
    be compromised by therapeutic drugs or even
    anxiety and severe depression.
  • Sometimes, the cancer itself can suppress the
    immune system.

32
Useful References for Section 2
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • Cancer Backup Retinoblastoma in Children
  • InfoTrac Study IDs Gene Triggers to Liver
    Cancer. Jamie Talan. Newsday (Melville, NY), June
    28, 2006.
  • InfoTrac Scientists Link Gene to Metastatic
    Cancer. UPI NewsTrack, July 3, 2006.

33
Section 3
  • Assessing the Cancer Risk from Environmental
    Chemicals

34
Assessing the Cancer Risk from Environmental
Chemicals
  • According to the American Cancer Society, factors
    in the environment account for half of all
    cancers these factors include UV light,
    radiation, and industrial and agricultural
    chemicals.
  • Roughly 40 of the food
  • in supermarkets in the
  • U.S. contains pesticide
  • residues some of these
  • pesticides are banned in
  • the U.S., but come in on imports.

Figure 23.6
35
Assessing the Cancer Risk from Environmental
Chemicals
  • More exposure comes from pesticides used in
    community and home spraying.
  • The Ames test,
  • developed by
  • biochemist Bruce
  • Ames, uses bacteria
  • to test for the
  • mutagenic potential
  • of various chemicals.

36
Useful References for Section 3
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • InfoTrac Science That Sticks Chemists Work
    behind U.S. Decision to Ban PFOA. Canadian
    Chemical News, Mar. 2006.
  • EPA Carcinogens

37
Section 4
  • Diagnosing Cancer

38
Diagnosing Cancer
  • Early and accurate diagnosis of cancer is
    important for maximizing the success of treatment.

Figure 23.7
39
Diagnosing Cancer
  • There are seven general warning signs of cancer
    (CAUTION)

40
Diagnosing Cancer
  • Various tests can be performed to confirm or rule
    out cancer.
  • Blood tests can detect tumor markers, such as HCG
    or PSA (prostate-specific antigen).
  • Radioactively labeled monoclonal antibodies are
    useful in pinpointing the location and size of
    certain tumors medical imaging techniques such
    as MRI, X rays, ultrasound, and CT are also used
    to locate tumors.

41
Diagnosing Cancer
  • The definitive detection tool is biopsy, removal
    of a small piece of tissue for microscopic
    examination.
  • A snippet of radioactively labeled DNA, called a
    DNA probe, can be used to locate gene mutations
    however, it is expensive and usually not covered
    by insurance.

42
Recommended Cancer Screening Tests
43
Useful References for Section 4
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • Oncology Nursing Society Cancer Symptoms
  • Mayo Clinic Diagnosing Cancer
  • InfoTrac Early Cancer Diagnosis Present and
    Future. Andre Baron et al. Patient Care for the
    Nurse Practitioner, Sept. 2005.

44
Section 5
  • Some Major Types
  • of Cancer

45
Some Major Types of Cancer
  • Cancers are named according to the type of tissue
    where they are first formed.
  • Sarcomas are cancers of connective tissues.
  • Carcinomas arise from epithelium, including skin
    and epithelial linings of internal organs.
  • Cancers of glands are adenocarcinomas.
  • Lymphomas are cancers of lymph tissue.
  • Cancer of stem cells or bone marrow is leukemia.

46
Some Major Types of Cancer
  • The following conclusions are drawn from the
    cancer statistics in Figure 23.8.
  • Highest cancer incidence maleprostate
  • femalebreast.
  • Highest cancer deaths both male and
    femalelung.

47
Fig 23.8, p.434
Cancer Incidence by Site and Sex
Cancer Deaths by Site and Sex
MALE
MALE
FEMALE
FEMALE
prostate 232,090
lung and bronchus 90,490
lung and bronchus 73,020
breast 211,240
lung and bronchus 93,010
lung and bronchus 79,560
prostate 30,350
breast 40,410
colon and rectum 73,470
colon and rectum 71,820
colon and rectum 27,750
colon and rectum 28,540
urinary bladder 47,010
uterus 40,880
ovary 16,210
pancreas 15,820
leukemia 12,540
melanoma of the skin 33,580
non-Hodgkin lymphoma 27,320
pancreas 15,980
esophagus 10,530
leukemia 10,070
non-Hodgkin lymphoma 29,070
melanoma of the skin 26,000
liver 10,330
non-Hodgkin lymphoma 9,050
kidney 22,490
ovary 22,220
non-Hodgkin lymphoma 10,150
leukemia 19,640
thyroid 19,190
uterus 7,310
oral cavity 19,100
urinary bladder 16,080
urinary bladder 8,970
multiple myeloma 5,640
pancreas 16,080
pancreas 16,100
brain 5,480
kidney 8,020
all sites 710,040
all sites 662,870
all sites 295,280
all sites 275,000
Excludes basal- and squamous-cell skin cancer
and in situ carcinomas except urinary bladder.
48
Video Fighting Sarcoma
  • This video clip is available in CNN Today Videos
    for Anatomy and Physiology, 2004, Volume VIII.
    Instructors, contact your local sales
    representative to order this volume, while
    supplies last.

49
Useful References for Section 5
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • InfoTrac Sarcomas Most Common Cancer Type in
    Teenagers. GP, April 7, 2006.
  • InfoTrac Mutations Point the Way to New Leukemia
    Drugs. Ascribe Higher Education News Service,
    July 17, 2006.
  • Abramson Cancer Center Oncolink
  • Association of Cancer Online Resources Types of
    Cancer

50
Section 6
  • Treating and
  • Preventing Cancer

51
Treating and Preventing Cancer
  • Chemotherapy and radiation kill cancer cells
    directly.
  • Chemotherapy uses drugs to kill cancer cells.
  • The cancer drugs disrupt DNA replication during S
    phase or prevent mitosis by inhibiting the
    formation of the mitotic spindle.
  • These drugs are also toxic to rapidly growing
    human cells, such as hair cells, stem cells, and
    epithelial cells.

52
Treating and Preventing Cancer
  • Radiation kills both cancer cells and the healthy
    cells around them.
  • Adjuvant therapy combines less-toxic chemotherapy
    with surgery to remove the tumor.
  • Monoclonal antibodies are used to deliver lethal
    doses of radiation or anticancer drugs to tumor
    cells specifically.
  • Immunotherapy is the use of substances such as
    interferon and interleukins to activate cytotoxic
    T cells to attack the cancer.

53
Treating and Preventing Cancer
  • Anticancer drugs may be matched to genetic
    characteristics of cancer cells.
  • Traditional chemotherapy drugs were matched to
    the organ where the cancer occurs.
  • New strategies aim to match therapy with the
    specific genetic characteristics of the cancerous
    cells, regardless of where the cancer occurs.

54
Treating and Preventing Cancer
  • You can limit your cancer risk.
  • We cannot control heredity of some aspects of
    biology, but we can make choices to affect our
    own health.
  • Some strategies for limiting cancer include
  • Avoid tobacco in any form.
  • Maintain desirable weight.
  • Eat a low-fat, high-fiber diet.
  • Restrict alcohol intake.
  • Avoid hazardous chemicals
  • in the workplace.
  • Avoid excessive sun exposure.

Figure 23.9
55
Video Prostate Cancer Prevention
  • This video clip is available in CNN Today Videos
    for Anatomy and Physiology, 2004, Volume VIII.
    Instructors, contact your local sales
    representative to order this volume, while
    supplies last.

56
Useful References for Section 6
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • National Cancer Institute Clinical Trials
  • Cancer Research Institute
  • InfoTrac HPV DNA Testing and HPV Vaccines
    Described by Experts as Combination That Offers
    Best Hope of Preventing Cervical Cancer. PR
    Newswire, April 27, 2006.

57
Section 7
  • Cancers of the Breast and Reproductive System

58
Cancers of the Breast and Reproductive System
  • Breast cancer is a major cause of death.
  • Breast cancer ranks second to lung cancer as a
    cause of death in females.
  • Causative factors include obesity, late
    childbearing, early puberty, late menopause,
    excessive estrogen,
  • and familial history.
  • Early detection by breast examination and
    mammography are keys to cure.
  • Treatment methods include modified radical
    mastectomy and lumpectomy some drugs such as
    tamoxifen are also used.

59
Fig 23.10b, p 436
1. Lie down and put a folded towel under your
left shoulder,then put your left hand behind your
head. With the right hand (fingers flat), begin
the examination of your left breast by following
the outer circle of arrows shown. Gently press
the fingers in small, circular motions to check
for any lump, hard knot, or thickening. Next,
follow the inner circle of arrows. Continue doing
this for at least three more circles, one of
which should include the nipple. Then repeat the
procedure for the right breast. For a complete
examination, repeat the procedure while standing
in a shower. Hands glide more easily over wet
skin.
2. Stand before a mirror, lift your arms over
your head, and look for any unusual changes in
the contour of your breasts, such as a swelling,
dimpling, or retraction (inward sinking) of the
nipple.Also check for any unusual discharge from
the nipple.
If you discover a lump or any other change during
a breast self-examination, its important to see
a physician at once. Most changes are not
cancerous, but let the doctor make the diagnosis.
60
Cancers of the Breast and Reproductive System
  • Uterine and ovarian cancer affect women.
  • Uterine cancer rates are declining due to early
    detection, mainly by Pap smear.
  • Ovarian cancer is often lethal because symptoms
    do not occur until the cancer is advanced the
    chemical taxol has been used with moderate
    success.

61
Cancers of the Breast and Reproductive System
  • Testicular and prostate cancer affect men.
  • Testicular cancer is painless in its early stages
    but may spread to the lymph nodes and eventually
    to the lungs surgery is the usual treatment.
  • Prostate cancer is second only to lung cancer in
    causing cancer deaths in men a PSA blood test is
    diagnostic, and cure rate is high for cancers
    detected early.

Figure 23.11
62
Video Breast Cancer Treatment
  • This video clip is available in CNN Today Videos
    for Anatomy and Physiology, 2003, Volume VII.
    Instructors, contact your local sales
    representative to order this volume, while
    supplies last.

63
Useful References for Section 7
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • InfoTrac Tylenol Lowers Ovarian Cancer Risk. UPI
    NewsTrack, July 10, 2006.

64
Section 8
  • A Survey of Other Common Cancers

65
A Survey of Other Common Cancers
  • Oral cancers occur in the lips, mouth, tongue,
    salivary glands, and throat and are most common
    among users of any form of tobacco most of the
    cancers are highly deadly.

66
A Survey of Other Common Cancers
  • Lung cancer kills more people than any other
    cancer.
  • The overwhelming risk factor is smoking, a
    practice that is declining in men but increasing
    in women.
  • Lung cancers include squamous cell carcinomas,
    adenocarcinomas (large-cell carcinomas), and
    small-cell carcinomas.

67
A Survey of Other Common Cancers
  • Cancers of the stomach and pancreas are usually
    adenocarcinomas of the duct cells and are usually
    not detected until they have spread.

68
A Survey of Other Common Cancers
  • Most cancers of the colon and rectum (colorectal
    cancers) are adenocarcinomas.
  • The cancers generally start
  • as small polyps (growths).
  • Warning signs include blood
  • in the feces a family history
  • of colorectal cancer or
  • inflammatory bowel disease
  • is a major risk factor.

Figure 23.12
69
A Survey of Other Common Cancers
  • Urinary system cancers.
  • Carcinomas of the kidneys and bladder are related
    to smoking and industrial chemicals.
  • Wilms tumor is an inherited type of kidney cancer
    that appears most often in children.

70
A Survey of Other Common Cancers
  • Cancers of the blood and lymphatic system.
  • Lymphomas, such as non-Hodgkin lymphoma,
    Hodgkins disease, and Burkitt lymphoma, seem to
    increase with infections that impair the immune
    system.
  • Leukemiascancers of the stem cells of the bone
    marrowlead to overproduction of white blood
    cells treatment is with chemotherapy, especially
    the plant derivatives vincristine and
    vinblastine.

71
A Survey of Other Common Cancers
  • Skin cancers are the most common of all cancers.
  • Malignant melanoma, cancer of the melanocyte
    cells, metastasizes aggressively.
  • Squamous cell carcinomas start out as scaly,
    reddened bumps that grow rapidly and can spread
    to adjacent lymph nodes.
  • Basal cell carcinomas grow slowly into ulcers
    with beaded margins.

72
A Survey of Other Common Cancers
  • Basal cell carcinoma and squamous cell carcinoma
    are more common than malignant melanoma and can
    be easily treated with minor surgery.

73
Video Skin Sun Damage
  • This video clip is available in CNN Today Videos
    for Biology, 2003, Volume VII. Instructors,
    contact your local sales representative to order
    this volume, while supplies last.

74
Video Custom Cancer Vaccine
  • This video clip is available in CNN Today Videos
    for Anatomy and Physiology, 2003, Volume VII.
    Instructors, contact your local sales
    representative to order this volume, while
    supplies last.

75
Useful References for Section 8
  • The latest references for topics covered in this
    section can be found at the book companion
    website. Log in to the books e-resources page at
    www.thomsonedu.com to access InfoTrac articles.
  • InfoTrac American Academy of Dermatology Warns
    of Skin Cancer Risks This Summer More Than 1
    Million New Cases of Skin Cancer to Be Diagnosed
    This Year in U.S. Internet Wire, July 7, 2006.
  • Mayo Clinic Pancreatic Cancer
  • American Cancer Society All About Colon and
    Rectum Cancer
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