Unit 3: How to conquer cancer

learn shi about cancer,

Behavioral risk factor

something you can change

ex// smoking

Biological risk factor

physical characteristics

ex// age, sex, race

Environmental risk factor

Things found in surroundings

ex// toxins, asbestos

Genetic risk factor

Traits inherited from parents

ex// BCRA genes

How many people will get cancer in the US

1/2 of men, 1/3 of women

1st and 2nd leading causes of death in the US

Heart disease and cancer, respectively

cancer risk factors are…

factors that increase chances of developing cancer (but do not guarantee it!)

Conclusions about cancer

* cancer can occur in any tissue or organ
* early detection/treatment → better prognosis
* incidence of cancer increases with age
* behavior can increase cancer risk
* treatment includes: chemo, radiation, surgery, cell/bone marrow transplant
* family history can increase chance of cancer

How do X-Rays work and what type of image do they produce?

Electromagnetic radiation sent through body to produce 2D images

How do images from X-Rays look?

White - dense structures (bone)

Black - other structures containing air

Grey - muscle, fat, liquid

What is CT/CAT scan the abbreviation of?

Computerized (Axial) Tomography

How do CT scans work?

Specialized x-rays provide cross-section images of body

What is the risk of getting x-ray scans (x-ray, CT scan)?

Radiation can cause mutations in DNA and thus could cause cancers to develop

How does an MRI (Magnetic Resonance Imaging) work?

Uses magnets and radio waves (NOT x-rays) to produce detailed images of soft tissue, including brain.

also cannot be used with any metal on the body due to the types of waves

Cell division in normal vs cancer cells

Normal cells: divide in organized matter and die after a certain number of divisions

Cancer cells: divide indefinitely, resulting in large number of irregularly shaped cells

Cell features in normal vs cancer cells

Normal cells: distinct features to perform specialized function

Cancer cells: lose specialized features and therefore cannot execute function or function incorrectly

Cell size and shape in normal vs cancer cells

Normal cells: cells of same tissue are same size and shape

Cancer cells: vary in size and shape

Nuclei in normal vs cancer cells

Normal cells: one small nucleus

Cancer cells: large nuclei in variable shapes

Cell arrangement in normal vs cancer cells

Normal cells: organized, well defined tissue boundaries

Cancer cells: disorganized arrangement, tissue boundary poorly defined

How do normal cells respond to signals?

receive signals which tell the cells when to start and stop dividing

if a cell is damaged the cell will undergo apoptosis and kill itself

How do cancer cells respond to signals?

cancer cells DO NOT receive signals and will divide indefinitely, forming a tumor. cells will call for more food by growing blood vessels toward them

What is apoptosis?

Cell undergoes process to “kill itself” when it has done its job

What is angiogenesis?

formation of new blood vessels (for tumor alimentation)

What is metastasis?

When cancer cells start spreading to other parts of the body

What two genes are associated with cancer?

proto-oncogene (just called “oncogene“ when mutated) and tumor suppressor gene

What is a proto-oncogene’s role?

“Go signal” for cell division

What is a tumor suppressor gene’s role?

“Stop” signal for cell division

Why are tumor suppressor gene problems less common?

The mutations are recessive and there are two copies of each gene. If one copy is mutated, then the other one will function fine. If both of them are broken, however, cell division will not stop

what does the TP53 gene do?

it is a tumor suppressor gene that activates DNA repair enzymes

How do genes become mutated?

mutations are caused by a change in DNA, brought upon by chemicals, radiation, viruses, or changes that are simply hereditary

How are different cells developed?

All cells have all of your DNA, but different genes get turned on during cell differentiation in order to make specified proteins

What is DNA Microarray used for?

used to look at 1000s of genes at once and measures the amount of mRNA in order to determine which genes are on and off. used to compare gene expression in normal and cancer cells.

DNA Microarray steps

1. collect tissue
2. isolate RNA from cells, separate mRNA
3. make labeled cDNA from mRNA (complementary)


1. use different fluorescent nucleotides for health vs cancer cells
4. apply cDNA onto microarray chip
5. scan microarray

What does each color (yellow, green, red) in a DNA microarray chip mean?

Yellow: gene expressed in both healthy and cancer cells

Green: genes that produce more mRNA in healthy cells compared to cancer cells

Red: genes that produce more mRNA in cancer cells compared to healthy cells

What does the color intensity in the DNA microarray represent?

measurement of gene expression level. The more intense the color, the more the gene is turned on

What is the purpose of using DNA microarray?

used to identify what genes could play a role in causing, intensifying, or preventing cancer

What does the Pearson Correlation Coefficient do?

statistically measures the relationship between two sets of data

positive correlation coefficient

things being compared behave similarly. the closer the value is to 1, the stronger the relationship is

negative correlation coefficient

things being compared behave in opposite ways. the farther the value is from 0, the stronger the relationship

correlation coefficient of 1 or 0

both things behave identically -- both things’ behavior is unrelated

Dendrogram

Common cancer risk factors

smoking (or smoke exposure), bad diet, lack of exercise, obesity, old age

Lung cancer screening

low-dose CT scan

Breast cancer screening

mammogram, MRI

Cervical cancer screening

HPV (virus) test or Pap smear

Colon cancer screening

colonoscopy

What are the 2 genes associated with inherited breast cancer? What type of gene are they>

BRCA1 and BRCA 2. Both are tumor suppressor genes.

3 Types of cancers

1. Sporadic: no family history. random mutation
2. Hereditary: mutations are passed on from parent to kid (BRCA genes, Colon cancer)
3. Familiar: combination of genetic and environmental risk0

What is Marker Analysis and what it is used for?

test for marker (short DNA sequence associated with a particular gene)

Where is the BRCA 2 marker?

Chromosome 13, next to the BRCA 2 gene