3.1 Detecting cancer Flashcards
5 risk factors for Cancer
Smoking
Radiation/UV ray exposure
Viral Infections
Genetic Mutations
Unhealthy Lifestyle
Cancers associated w/risk factor
- Smoking - Lung, oral, colon, bladder, & breast cancers
- Radiation/UV ray exposure - Skin cancer
- Viral Infections - HPV=cervical cancer, Epstein-Barr virus= lymphoma, Hep B= liver cancer
- Genetic Mutations (inherited) - BRCA1 & BRCA2 mutations breast & ovarian cancer
- Unhealthy Lifestyle (overweight, no exercise) - Colon & prostate cancer
most ______ perform ______ _____ to help identify & start to treat medical conditions
radiologists
diagnostic imaging
imaging can clue in on cancers like_______ _____ _____can identify tumor in bone, MRI can identify strange masses in bone (especially when cancer has metastasized), bone scan shows entire skeleton & where cancer has spread (tracks active bone changes “hot spots”)
osteosarcoma
x-ray
Images of bones, teeth, lungs,
breasts, heart, blood vessels,
digestive tract
X-ray
- Computerized (Axial) Tomography
- VERY DETAILED images -> especially of
bones, chest, abdomen, pelvis, spine,
brain
CT scan
Magnetic Resonance Imaging
Brain, spine, joints, abdomen,
blood vessels, pelvis
MRI
- Type of nuclear imaging test
Helps diagnose & track several
bones diseases & cancers like
osteosarcoma
Bone scan
VERY DETAILED images
CT scan
NO RADIATION= SUPER SAFE
MRI
EXTREMELY SENSITIVE
Bone scan
Quick & painless, but exposed to
radiation
MAY have to inject a contrast dye
to help w/ imaging
Hard to be done on ppl w/
implanted devices
X-ray
Painless & non-invasive
More detail than X-ray more accurate
diagnoses of cancers like lung, bowel,
liver, & kidney cancers
Can be done on ppl w/ implanted metal
devices
Exposed to radiation
CT scan
NO RADIATION= SUPER SAFE
Great detail of soft tissue
identification & diagnoses of
diseases
MRI
EXTREMELY SENSITIVE to
variations in bone metabolism &
abnorms.
Small amt. radiation
Bone scan
Procedure:
Machine send photons (X-ray
particles) into body to come in
contact w/ tissues & produce
image on metal film
Shows 2D image
Dense structures like bone appear
white b/c absorb radiation
Structures including air appear
black
Muscle, fat, fluid appear gray
X-ray
Procedure:
Performed in large X-ray tube patient
lays down & is inserted into tube
Tube rotates around patients to get
multiple images of different slivers of
body
Multiple X-ray images from different
angle produced cross-sectional
images of bones & soft tissue
CT scan
Procedure:
Performed inside large,
magnetic tube
Person lies down while
machine scans body by turning
small magnets on & off within
tube
Magnets send radio waves thru
body waves bounce back &
are interpreted by MRI
machine to produce image
Produces cross-sectional
images, especially for SOFT
TISSUES
MRI
Procedure:
Injected w/ tracers (tiny
radioactive particles called
radionuclides) that will circulate
thru body & get absorbed into
bones
Patient lies on table while
machine passes a gamma
camera over them to record
patterns of tracer absorption
2D images that examine
skeleton for abnorms.
Bone scan
a malignant tumor of cells growing uncontrollably
cancer
50 divisions, but cancer cells grow indefinitely
Cell cycle limit
______ _____ gets damaged when dividing & breaks free from normal cell division limits
ONE CELL
_____ ___ ____ in nucleus often cancer
changes in DNA
cells typically die after 50 divisions. Why?
prevents them from becoming too damaged
____ occur spontaneously or b/c of radiation & chemicals
mutations
____ occur spontaneously or b/c of radiation & chemicals
mutations
CANCEROUS cells ____ ____ (tumors) & in ___ ___ ___ ___
different shapes & sizes
ALL CANCEROUS CELLS ARE UNIQUE FROM EACHOTHER treatments only kill SOME of the
cancer cells, while others are resistant
-
To identify cancer, will first do screenings then a ____ will confirm malignant cells
biopsy
_____ “cell suicide” that SHOULD occur when DNA is damaged; cancer cells won’t
undergo apoptosis
Apoptosis
______ vessels created that connect to tumors – FEED tumors & let them spread
Angiogenesis
-______ “everywhere staying” – when tumor spreads from original tumor post angiogenesis
Metastasis
_____- a transcription factor that codes for the transcription of a gene that will release protein to
end cell cycle – triggers the release of a protein that induces apoptosis
p53
“accelerator/GAS PEDAL”
Responsible for telling cells when to divide
-> only when need new cells
HEALTHY = PROTO-ONCOGENE
Are induced/turned up in cancer cells
Like the “gas pedal being stuck down”
will allow cells to divide without necessary
signals
When cells allowed to grow infinitely, more
likely to mutate CAUSE cancer
CANCEROUS = ONCOGENE
“brakes” of cell division
Responsible for telling cells to stop dividing once
enough cells have been created
Have two copies of genes even if one damaged,
can still stop division – p53 gene
HEALTHY= TUMOR SUPPRESSOR GENE
Suppressed/turned down in cancer
No longer stop cell division cancerous cells
continue to grow w/ mutated DNA
CANCEROUS = MUTATED TUMOR SUPPRESSOR GENE
“editors of the newspaper” –ACTIVE
WITHIN THE CELL CYCLE
code for proteins that fix errors in DNA
TYPE of tumor suppressor gene
Needed to prevent cancer
CANCEROUS = MUTATED DNA RE
HEALTHY= DNA REPAIR GENE
Suppressed/turned down by cancer
“drunk editors” not doing their job to fix
the DNA
BRCA1 & BRCA2
CANCEROUS = MUTATED DNA REPAIR GENE
___ ____ = gene “chip” that allows us to look @ thousands of genes
at once study GENE EXPRESSION
DNA microarray
PROCESS:
1. Collect Tissue Samples
2. Isolate RNA - (dissolve sample into solution so RNA stays in supernatant
& all else trashed)
3. Isolate mRNA – only mRNA contain “Poly-A” tails, so wash the RNA over
columns w/ small beads that will bind w/ tails then rinse into other tube
4. Make Labeled DNA Copy – add green labeling mix to healthy sample &
red to cancerous (labeling mix= make complementary DNA strands to
the RNA (cDNA) that correspond to genes)
5. Apply DNA- (little piles of single-stranded DNA already on microarray;
each spot has identical copies of one gene that’s tracked in computer
database); add cDNA from mix & the stands will bind onto spots
6. Scan Microarray – scan green & red separately, then combine image
7. Analyze Data
DNA microarray
___= expressed in healthy cells, but TURNED DOWN in cancer (b/c no
red cDNA attached) mutated like mutated tumor suppressor genes
Green
____= not expressed in healthy cells, but TURNED UP in cancer (b/c no
green cDNA attached) mutated like oncogene
Red
____= expressed EQUALLY in healthy & cancerous cells, expression not
affected by cancer no mutation
Yellow
____= gene expressed in NEITHER healthy or cancerous cells
BLACK
Convert colors to numbers
based on intensity of red &
green the____ the
color, the_____ the number
BRIGHTER
HIGHER
Ratio GREATER than 1 =
gene induced by tumor formation (red>green)
Ratio LESS than 1 =
gene suppressed by tumor formation (green> red)
Ratio EQUAL TO 1 =
gene not affected by tumor growth
(green copies=red copies)
Ratio of ZERO =
gene not expressed in either cell (black)
positive =
gene expressions behave similarly
positive =
gene expressions behave similarly
negative =
gene expressions behave oppositely
one=
gene expressions identical
zero =
gene expressions behave in unrelated manner
