Transcript Cancer: Cell division gone wrong

Cancer:
Cell division gone wrong
Checkpoints in cell cycle
Is the DNA fully
replicated?
 Is the DNA
damaged?
 Are there
enough nutrients
to support cell
growth?

Monitored by specialized proteins which send
messages to nucleus to cell what to do
http://youtu.be/VhkQP5g4EHo
A Basic Definition
Cancer is defined as:
 Disease caused by
uncontrolled growth
and division of
defective cells.

daughter cells continue
this destructive cell
reproduction cycle
Cell Growth Rates and Cancer

Cancer occurs when:
– Despite messages to STOP, a defective cell
continues to grow and divide
-a tumour is a lump of defective cells that develops
The Two Types of Tumours
1. Benign
Tumours
2. Malignant
Tumours
1. Benign Tumours

Noncancerous lumps

Only harmful if the
lumps physically crowd
nearby tissues
2. Malignant Tumours
Cancerous
 Interfere with the regular functioning of
surrounding cells and tissues
 May lead to metastasis

metastasis:
occurs when
malignant tumour cells break
off and form a secondary
tumour elsewhere in the body
eg. Renal (kidney) cancer
Why is metastasis dangerous?

Metastatic tumours may spread to vital areas
(blood, lungs etc..) and resulting in more severe
health problems

Multiple locations of cancer are more difficult to
treat.
Cancer cannot
spread without a
network of blood
vessel to support

Image from:
http://www.cancer.gov/cancertopics/understandingcancer/angiogenesis/AllPages
What causes of Cancer?
There are three general causes of cancer
Mutations Caused by:
1. Random Error Mutation during DNA
replication
2. Carcinogens
3. Genes (Oncogenes)
Random Error Mutations as a cause
for Cancer

Errors in DNA duplication may occur during cell
division
When does DNA duplication occur?
S phase of cell cycle right before cell division

Usually, harmful mutations cause the cell to
self-destruct or refrain from dividing.
Carcinogens


Environmental factors that cause mutations
in DNA
For example:
1. Tobacco smoke
Carcinogens

Environmental factors that cause mutations
in DNA

For example:
2. Radiation
Such as UV rays (sun/tanning beds)
Carcinogens

Environmental factors that cause mutations
in DNA

For example:
3. Chemicals like BPA
(bisphenol A)
Carcinogens

Environmental factors that cause mutations
in DNA

For example:
4. Viruses
(HPV-human papillomavirus can stay in the body
and lead to cervical cancer)
Cause of Cancer (Cont.): Oncogenes

Defective genes (due to mutations) are
passed down from one generation to
another
Oncogenes

Family history can
indicate presence of
oncogenes
(Oncology
the study of
cancer)
is
• Examples of cancer
that tend to run in
famillies:
breast cancer & colon
cancer
Different Kinds of Cancer
Some common
carcinomas:
Lung
Leukemias:
Bloodstream
Lymphomas:
Lymph nodes
Breast (women)
Colon
Bladder
Prostate (men)
Some common
sarcomas:
Fat
Bone
Muscle
Examples of cancer
types
Breast cancer 
 Colon cancer
http://www.colorectalcancer.ca/en/just-thefacts/symptoms/
Which is the healthy lung? Which
cancerous?
Healthy
Cancerous
Smoking as a cause for Cancer



9 out of 10 cases of lung cancer in Canada are a
result of smoking
Lung cancer is the most common type of cancer in
Canadians over 40
Can you explain why cigarettes are so expensive
and why many Canadian bars/clubs are smokefree?
Population-Based Studies
U.K.:
Lung
cancer
Regions of Highest Incidence
CANADA:
Leukemia
JAPAN:
Stomach
cancer
CHINA:
Liver
cancer
AUSTRALIA:
Skin
cancer
U.S.:
Colon
cancer
BRAZIL:
Cervical
cancer
Detecting Cancer


Early detection of cancer is important to
prevent metastasis
3 basic screening methods include:
1. Genetic testing (for breast or colon cancer)
2. Self-exams (breast or prostate)
3. Medical diagnostics
Medical Diagnostic Tools

Endoscopy
–
–
Fibre optic cable is inserted into
the body cavity to look for
suspicious growths
Commonly used to detect colon
cancers
Observe a colonoscopy
https://www.youtube.com/watch?v=ewCIqA
AJGPg
Pill camera:
https://www.youtube.com/watch?v=AlQN3c0
4mu0
Medical
Diagnostics

X-Rays
–
–
Images used to detect
cancer in bones and
lung tissue
Mammogram is a
specialized x-ray to
examine breast tissue
Medical Diagnostics

Ultrasound
– Sound waves are
used to examine
soft tissue
– Detects cancers in
heart or liver
tissue
Using ultrasound
technology helps avoid
the use of harmful Xrays (as in CAT scan)
Medical Diagnostics

CT/CAT Scan
(computerized
axial
tomography)
–
–
X-ray images
taken from
various angles to
access hard to
see tissues
Often used to
detect brain
cancer
Medical Diagnostics

MRI (magnetic
resonance
imaging)
– Radio waves and
magnetic fields
generate 3D
images with
greater detail
than CT scans
Medical Diagnostics

Examining Cells and
Biopsy
–
–
Cells are taken via blood
samples or surgery and
then examined under a
microscope
Based on irregular shape
and smaller size,
cancerous cells can be
identified
Conventional Cancer Treatments

1.
2.
3.
Cancer is generally treated in three ways:
Surgery
Chemotherapy
Radiation
Surgery as Cancer Treatment




Cancerous tissue is excised
(cut) from the body
Benefits:
Ensures that most of the
cancerous cells are physically
removed
Disadvantage:
Surgery can be risky, especially
in the elderly and infirm
Chemotherapy




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Drugs delivered to slow or stop cancer cell division.
(May kill cancer cells sometimes)
Benefits:
Shrinks tumours for later surgical removal or
radiation treatment- even small, hard-to- reach
tumors
Disadvantage:
Suffering from side effects (hair loss, nausea, fatigue)
May affect healthy cells but they can repair
themselves
Radiation





A focused beam of
gamma radiation kills or
damages cancer cells
Benefits:
Can precisely target even
small tumours
Disadvantage:
May cause radiation sickness.
Also radiation exposure can
potentially cause other
cancers.
Recent advancement
https://www.youtube.com/watch?v=M1WdL61y_S8&feature=youtu.be
The End