Developmental Biology

2. Cancer is a large group of
diseases (over 200)
characterized by
uncontrolled growth and
spread of abnormal cells.*
**American Cancer Society, Cancer Facts and Figures 2005American Cancer Society, Cancer Facts and Figures 2005

3.  Oncogenes are mutated forms of cellular
proto-oncogenes.
 Proto-oncogenes code for cellular proteins
which regulate normal cell growth and
differentiation.
33

4.  Carcinogens
 Chemical- e.g. benzo(a)pyrene
 Radiation- e.g. X rays
 Viruses
 Hereditary predisposition

5.  Cancer cells:
 Lose control over growth and
multiplication
 Do not self-destruct when they
become worn out or damaged
 Crowd out healthy cells

6.  Cells in culture and in
vivo exhibit contact-
inhibition
 Cancer cells lack contact
inhibition feedback
mechanisms. Clumps or
foci develop.

7.  Size of cancer cells:
 One million cancer
cells = head of a pin
 One billion cancer
cells = a small grape
 230
= 1,073,741,824
= 1 billion cells
2-6 weeks
 Cancer cells reproduce every
2-6 weeks.
2-6 weeks
2-6 weeks

8.  1st
Mutation: alteration of DNA and
reproduction of genetically altered cell
 2nd
Mutation: further mutation, may have
different appearance and more prone to
division
 3rd
Mutation: further mutation, speeds up the
growth of the tumor
 4th
Mutation: further mutation, causes the
development of more aggressive cancer

10. 1. Growth Factor Receptor Increased
numbers in 20 percent of breast cancers
2. Ras Protein Activated by mutations in
20 to 30 percent of cancers
3. Abl Kinase Activated by abnormal
chromosomes in chronic myelogenous
leukemia
4. Src Kinase Activated by mutations in 2
to 5 percent of cancers
5. p53 Protein Mutated or deleted in 50
percent of cancers

11.  Benign tumours do not spread from their site of origin, but
can crowd out (squash) surrounding cells
 e.g. brain tumour, warts.
 Malignant tumours can spread from the original site and
cause secondary tumours.
 This is called metastasis. They interfere with neighbouring cells
and can block blood vessels, the gut, glands, lungs etc.

12.  metastasis – establishment of new tumour
sites at other locations throughout the body.

13. MetastasisMetastasis
Carcinoma: derived from endodermCarcinoma: derived from endoderm
or ectodermor ectoderm

15.  Change in bowel habits or bladder functions
 Sores that do not heal
 Unusual bleeding or discharge
 Lumps or thickening of breast or other parts of the
body
 Indigestion or difficulty swallowing
 Recent change in wart or mole
 Persistent coughing or hoarseness

16.  Carcinomas (cells
that cover internal and
external body surfaces)
Lung
Breast
ColonColon
BladderBladder
ProstateProstate
(Men)(Men)
Leukemia
(Blood Cells)
Lymphomas
(Lymph nodes
&tissues)
Sarcomas
Cells in supportive
tissues – bones &
muscles

17. Screening tests:
 Colon
 Breast
 Cervical
 Prostate
Self-exams:
 Testicular
 Skin

18. The treatment of cancer is
most successful when the
cancer is detected as early
as possible, often before
symptoms occur.

19.  Most colon cancers
start as a polyp
 Removing polyps can
prevent colon cancer
• AdvancedAdvanced
bleedingbleeding
cancercancer
• A polypA polyp

20.  Age of 50 and older; younger if
there is a family history
 Yearly fecal occult blood test (FOBT) or
 Flexible sigmoidoscopy every 5 years or
 Yearly FOBT and sigmoidoscopy every 5 years or
 Double-contrast barium enema every 5 years or
 Colonoscopy every 10 years
Of the options above ACS prefers yearly FOBT and Sigmoidoscopy every five yearsOf the options above ACS prefers yearly FOBT and Sigmoidoscopy every five years

21. • Breast cancer occurs primarily in women.
• Signs and symptoms involve changes in breast tissue:
▪ Risk factors
 Family history
▪ Women with mothers, sisters, or daughters who have
breast cancer
 Age
▪ Rare before age 20
▪ Risk increases throughout the 20s
▪ Rises dramatically during the 30s through mid-70s
(majority or cases occur in women 40 and over)
▪ Drops significantly after mid-70s

22.  Cervical cancer screening
should be done every year with
regular pap tests or every two
years using liquid based pap
tests.
 At or after age 30, women who
have had three normal test
results in a row may get
screened every two to three
years.

23.  Both prostate specific antigen (PSA) and digital
rectal examinations (DRE) are recommended for
men over 50 and who choose to undergo screening
for prostate cancer

24.  Examination of a man’s testicles is an important
part of a general physical exam. It is
recommended that a testicular exam be conducted
during routine cancer-related checkups.

25.  Fifth leading cause of cancer death for women,
20,180 new cases diagnosed reported in 2006
 Most common symptom is enlargement of the
abdomen
 Risk factors include: family history, age,
childbearing, cancer history, fertility drugs, talc use
in genital area, genetic predisposition
 Prevention: diet high in vegetables and low in fat,
exercise, sleep, stress management, and weight
control

26.  The ABCD’s of melanoma (skin
cancer):
 Asymmetry: one half is not like the
other
 Border: the edges are jagged or
irregular
 Color: the color is varied, tan, red,
black etc
 Diameter: the diameter is larger
than 8mm (the top of a pencil
eraser)
AA
BB
CC
DD

27.  It is important to:
 Protect your skin with hats, long sleeves and
sunscreen
 Do a self examination of your skin monthly
 Become familiar with any moles, freckles or other
abnormalities on your skin
 Check for changes once a month. Show any
suspicious or changing areas to your health care
provider.

28. • Tobacco smoking is the leading cause of various
cancers.
• 30% of cancer deaths, including 87% of lung cancer
deaths, are attributed to tobacco use.
• Smoking cigarettes is most common cause.
• Women are more susceptible to lung cancer than
men due to presence of the GRPR gene, which is
linked to the abnormal growth of lung cells and is
more active in women.

30.  Cigarette smoking is the
leading cause of preventable
death in the US
 Second hand smoke affects
everyone

31.  Cancer rates could
decline by up to 20% if
everyone consumed 5
fruits and vegetables a
day!*
 Cancer fighting
substances:
 Antioxidants
 Dietary fiber
 Carotenoids
 Flavenoids
*American Institute for Cancer Research, 1998.

32.  Men – 2 drinks per
day
 Women - 1 drink per
day

33.  Limit time outside,
between 10 a.m. & 4 p.m.
 Wear protective clothing.
Use wide-brimmed hats
and sunglasses.
 Prevent sunburns,
especially for children
under 18. Use waterproof
sunscreen of SPF 15 or
higher. Reapply as
directed.
 Avoid tanning beds.

34.  Exercise for 30 minutes or
more at least 4 days a week.

36.  Pancreatic Ductal Adenocarcinoma
 Usually detected at the later stages of the
cancer
 Survival rate is <5%

38.  Tumors of Pancreatic cancer have activating
mutations in the KRAS2 oncogene
 Transcription of mutant will produce an
abnormal Ras protein
 The Ras protein is “locked” in activated form,
therefore resulting in activation of
proliferative and survival signaling pathways

39.  95% of tumors have inactivation of
the CDKN2A gene
 which results to the loss of the p16 protein (a
regulator of the G1–S transition of the cell
cycle) and a corresponding increase in cell
proliferation.

40.  TP53 is abnormal in 50 to 75% of tumors,
permitting cells to bypass DNA damage
control checkpoints and apoptotic signals
and contributing to genomic instability

41.  Biomarkers- used for diagnosis
 CA19-9 – carbohydrate antigen which levels
are elevated in patients who have large
tumors

42.  Limitations of CA19-9
 It is not a specific biomarker for pancreatic cancer
 Levels maybe elevated in other conditions such as
cholestasis
 Patients who are negative for Lewis antigen a or b
(approx. 10% of patients with pancreatic cancer),
are unable to synthesize CA19-9

43.  Protein expressed by mesothelial cells
 Overexpressed in tumors includingpancreatic
cancer
 Identified by Jack Andrada as a biomarker for
detecting pancreatic cancer even for early
stages

44.  Used Paper Sensors
 Coated with nanotubes laced with mesothelin-
specific antibodies
 mesothelin was then tested against the paper
biosensor
 any change in the electrical potential of the
sensor strip was measured, before and after
each application.

45.  The antibodies would bind to the mesothelin
and enlarge.
 These would spread the nanotubes farther
apart which changes the electrical properties
of the network
 The more mesothelin present, the more
antibodies would bind and grow big, and the
weaker the electrical signal would become.

46.  10 ng/mL is considered the level of
overexpression of mesothelin consistent with
pancreatic cancer
 The sensor’s limit of detection sensitivity was
found to be 0.156 ng/mL

47.  It’s a simple and cheap blood test that has
many potential
 It could also be potentially used for other
types of cancer