Genetics of Cancer
Presented by Gina Reyes, Amie Fitzwater,
Brittany Anders-Larson, & Yoshie Tamura
• Cancer is Genetic, But Usually Not
• Characteristics of Cancer
• Origins of Cancer Cells
• Cancer Genes
• A Series of Genetic Changes Causes Some
• Environmental Causes of Cancer
• Evolving Cancer
• Key Concepts
Cancer is Genetic, But
Usually Not Inherited
• Whether cancer runs in your family or not,
cancer is estimated to affect one out of
every three people.
chart is from the
Cancer and Genes
• There are two types • Somatic mutations
of genetic changes Are not passed on to the next generation
and it happens in the course of a person’s
or mutations that lifetime usually later on in life. Most
cause cancer: cancer mutations occur in this manner (as
referenced in the pie chart).
• Germline mutations
Are passed from generation to generation.
There is a 50/50 chance of
inheriting cancer if either parent has a
genetic change. This type of cancer can
develop if a environmental trigger
mutates a somatic cell or if somatic
mutation mixes with an inherited gene.
Characteristics of Cancer
• Cell division – Cancer cells no longer respond to stop
signals and therefore can divide at a continuously fast rate
if the cancer is a cancerous tumor.
• Look of a cancer cell - Cancer cells look different
when compared to normal cells. Cancer cells are rounder.
This is also known as dedifferentiated.
• Growth of a cancer cell – Cancers can take many
years to grow (ei, lung cancer). Angiogenesis can make the
cancer spread further by using the capillary extensions.
Origins of Cancer cells
There are at least 4 situations that can lead to cancer at cellular level:
1.) Activation of stem cells: 2.) Dedifferentiation:
• A cancer cell may descend • Cells lose their distinguishing
from: characteristics (their specializations)
– A stem cell that produces due to a mutation occuring as the
differentiated daughter cells cells divide.
(specialized cells) that retains
the capacity to self-renew. 3.) Loss of balance at tissue
– Specialized cells that lose some level:
of their features but can still
• Normal cells favor differentiated cells (or
divide. daughter cells).
• Cancer stem cells produce • Tissues with abnormal balance will favor
both cancer cells and cells that can divide continually
• Eventually that shift in balance will create
abnormal specialized cells an excess amount of stem cells and
• Cancer stem cells are found progenitors which causes a tumor.
in cancers of the brain,
blood, and epithelium (lining 4.) Faulty Tissue Repair:
• If too many cells divide to fill in the space
tissues such in the breast, left by injured tissue, and those cells
colon, and prostate). keep dividing, an abnormal growth may
• When mutations activated oncogenes or inactivate tumor
suppressor genes, cancer occurs.
• Proto-oncogene: A gene that normally triggers cell division
when it is appropriate.
• When proto-oncogenes are turned on at the wrong time or
place they function as “oncogenes”. This may be the result
of either a mutation or a change in expression of the wild
• Also, a proto-oncogene that is moved near a gene that is
highly expressed then it will also be rapidly transcribed.
• Example: Proto-oncogenes are normally activated at the site of a
wound. If it is activated at a site other than the wound (as an
oncogene) it still stimulates mitosis and bumps up the growth
factor production. These new, un-needed cells become a tumor.
Activating an oncogene: Tumor Suppressors
Increasing expression in a new location: • Some cancer results from loss of a
• Placing proto-oncogene near a gene that gene that normally suppresses
boosts its expression. tumor formation by sending growth-
• Moving proto-oncogene next to a gene inhibiting signals.
that is normally very active. • Unlike activating an oncogene
– This can happen when a chromosome is
inverted or translocated, placing the gene (which usually gains a function) a
in an new environment. tumor suppressor gene mutation
– When translocation or inversion places a usually removes a function.
proto-oncogene next to an antibody gene
the immune system contributes to cancer. • Some of the best studied tumor
supressor genes are:
Fusion Proteins with New Functions: – Retinoblastoma: a rare childhood
• When a proto-oncogene moves near eye tumor
another gene and the gene pair is – P53 gene: a single gene that causes
transcribed and translated as if it were a variety of cancers when mutant
one gene. – BRCA1 (Breast cancer
– The double gene product, called a fusion predisposition gene 1): Familial
protein, activates or lifts control of a cell breast cancer
division. • Encodes a large protein that is
normally in the nucleus, where it
Receiving a Too-Strong Division Signal activates transcription of the genes
that respond to p53 protein.
• When a proto-oncogene recieves too • BRCA1: When functioning properly
many signals to divide the gene will they are necessary for DNA repair
replicate until it causes a tumor.
Stages in the
Development of Cancer
One example of such a misfortunate event, is the rapid
development of brain tumors:
• A protein called P53, with in the structure of our
chromosomes, seizes to withhold the development
• Followed by an interruption on chromosome 9,
creating an error in the chromosomes immunity to
• As the genes cell cycle freezes growth develops on
chromosome 7, putting mitosis to a halt.
• At the last stage of the tumors growth , the
existence of chromosomes 10 mysteriously vanish.
Cancer is commonly formed in
the instability of genes
The cause of cancer is greatly impacted by genetics.
• A mutation is found when the inner
chromosomal alignment of a gene
becomes imbalanced .
• The whole genome risks instability at
the cost of the gene known as the
“gatekeeper” (who is in charge of
directing the correct balance of
somiotic cell division and the balance
of natural cell death).
• If the gate keeper does not delegate
the motions of the cells properly , a
mutation could occur leading to
• Once a gene has mutated into a
cancerous condition. The affect and
stages of the mutation begin to
unfold, in the depths of our
chromosomal structures .
BUB1B (above) is an example of inherited cancerous
genes found commonly in young children. 10
By knowing your genetics
• Although preparation or prevention of a brain tumor may
be impossible to achieve. Such inheritable cancers like
colon cancers can be prevented . Thanks to the research
of Doctor Eldon Gardener in 1947, who uncovered the
link to the genetic inheritance of colon cancer.
• In a current day action towards the prevention of cancer.
Doctors today can check the colon for polyps, a growth in
the colon that can lead to cancer.
• The other preventive method is the ability to check stool
samples for APC, a protein when found nonexistent in
ones gene structure can lead to growth of colon cancer.
• The effect of such an inherited mutation causes the lining
of the colon not to die off in its three day existence like it
is supposed to.
By utilizing the environment
Although the fate of cancer can bestow among any • The website http://www.therapeasecuisine.com
one, inheritance of the gene may eliminate the idea gives information on how to personally prevent
of chance replacing it with fate. Yet, regardless of cancer. Listing ideas like, “Eat more variety of
vegetables and do not use supplements that
chance or fate, luckily thanks to research and the protect against breast cancer.”
ability to control some simple environmental
• Even our text book list off suggestions of
factors we may be able to slow down or even helpful choices to make in our diet such as,
delete the existence of cancer amongst our genes. “Vitamins D and E, soy bean compounds, green
tea and certain anti- inflammatory drugs.”
• Being aware of occupational hazardous such as
fumes, and chemicals, you may breath in at
work could potentially bring fourth the effect of
• Population studies, in which communities bear
recessive forms of cancer. Under go group
research have found environmental impacts
and genetic similarity.
• Case- control studies have also been created to
watch over a persons life and the environment
of one that eats a diet high in vegetables and
exercises regularly and on that does not.
Usually the individual with the healthier
regimen, out lives of prolongs the occurrence of
• Though we can not yet fix our DNA or genetic
structure, we can make healthy choices in life.
The choice to live a life free from smoking, a
healthy diet and regular exercise, despite your
genetic inheritance could save your life.
Evolving Cancer Diagnosis
• It is now possible to predict the likelihood of certain cancers.
• A few cancer treatments include: surgery, radiation, and
– Surgery: Removes tumors
– Radiation and Chemotherapy: non-selectively destroys rapidly dividing
• If a patient does radiation and chemotherapy, they will need drugs to protect
them from harmful side effects.
• New drugs have been discovered to fight specific types of cancer.
• Nowadays, we have more than fifty drugs that can stop the blood
supply to tumor.
• Using drugs and chemotherapy are useful ways to cure cancer but
it means the patient will undergo a longer treatment.
• There are several ways to find cancer but they don’t always
pinpoint the cause requiring further examination.
• Cancer is genetic, but not necessarily inherited.
• Cancer cells have different gene expression profiles
compared to the cells from which they descended.
• Cancer is caused by loss of cell division control.
• 4 situations at cellular level lead to cancer:
• Activation of stem cells that produce cancer cells,
dedifferentiation, loss of balance at tissue level, and faulty tissue
• Single genes (oncogenes and tumor suppressor genes,
when mutant, can cause cancer.
• Proto-oncogenes normally control cell cycle and become
oncogenes when they mutate, moved next to a highly expressed
gene, or form a fusion protein.
• Mutations in tumor suppressors removes a function
• A single mutant gene can destabilize chromosomes causing
a predecessor of cancer.
• Treatments for cancer target the characteristics of cancer
Internet: Author Unknown 2008, 2008 Cancer Registry Report. Washington
Adventist Hospital, http://www.adventisthealthcare.com/WAH
Internet: Author Unknown, Mutation Types in Human Cancer. Nature,
Internet: Author Unknown, BUB1B human: BUB1 budding uninhibited by
Internet: CartoonStock.com, “Antioxidants”.