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