Neoplasia Flashcards
How many cells compose the body? How many different types of cells?
30-40 trillion
200+ different types (epithelial, neurons, RBC, etc)
How many cells die each day in the human body?
100 billion cells die each day and are replaced by new cells
Describe neoplasia.
new, abnormal growth of tissue (uncontrolled)
does not wait for signals for new tissue growth
ignores signals to stop dividing
do not mature normally (differentiate)
do not die off to keep cell count constant
Define the following: adenoma, carcinoma, adenocarcinoma, sarcoma, lymphoma, melanoma, leukemia, blastoma.
adenoma: benign tumor derived from glandular cells
carcinoma: malignant tumor derived from epithelial cells
adenocarcinoma: malignant tumor derived from glandular
tissue
sarcoma: malignant tumor derived from bones or soft tissue
lymphoma: malignant tumor derived from lymphocytes
melanoma: malignant tumor derived from melanocytes
leukemia: malignant tumor of blood-forming tissues
blastoma: malignant tumor derived from precursor cells
How many periods are in the cell cycle?
4 (G1, S, G2, M)
What are quiescent cells capable of doing?
G0, can move into or out of G1
True or false: normally, the number of cells produced is not equal to the number of cells that die
false
number of cells produced=number of cells that die
What happens in each phase of the cell cycle?
G1: cell grows and prepares for DNA replication
S: DNA replication
G2: cell continues to grow and prepare for mitosis
M: cell stops growth and starts division
G0: cell has left cell cycle and stopped dividing
When do checkpoints occur in the cell cycle?
one in G1 (DNA synthesis check) and one in G2 (preparation for mitosis)
-apoptosis occurs if anything goes wrong
What is the significance of R (restriction point)?
cell has committed to the cycle for division
Describe each phase of the M phase.
prophase: condensation of chromatin and disappearance of
nucleus
metaphase: chromosomes align on the metaphase plate
anaphase: chromosomes split and move to the opposite poles
of the cell
telophase & cytokinesis: spindle disappears, nucleus reforms
and mother cell divides into two
daughter cells
What tells a cell to divide?
growth factors (cells only divide when they are told to do so by growth factors)
What are growth factors responsible for?
initiate and maintain transition through G1 to S phase
When does the restriction (R) point occur?
2-3 hours before onset of DNA synthesis
At which point in the cell cycle are growth factors not required?
beyond R point
What are the major checkpoint monitoring molecules?
cyclins
cyclin dependent kinases (CDKs)
p53 (DNA damage)
RB (restinoblastoma)
APC (anaphase promoting complex)
What is cell differentiation?
cells become specialized cells to carry out specific functions
develop certain structures or lose certain structures
What is cell apoptosis?
programmed cell death
no damage to neighboring cells
Which pathway is responsible for mediating cell apoptosis?
caspase signaling pathway
True or false: apoptosis is the same as necrosis and autophagy
false
necrosis: influx of fluid, everything swells and bursts
autophagy: cell consumes its organelles
What happens to a differentiated, “working” cell when it mutates?
they form benign tumors
What happens to an undifferentiated cell when it rapidly divides and mutates?
they form malignant tumors
Describe benign tumors.
cells: similar to normal cells
growth: relatively slow, expanding mass
spread: localized
systemic effects: rare
life-threatening: only in certain locations (brain)
external surface: smooth
capsule: yes
necrosis: no
hemorrhage: no
Describe malignant tumors.
cells: varied in shape and size with large nuclei
growth: rapid growth, no cell adhesion
spread: local and distal metastasis
systemic effects: often
life-threatening: yes, by tissue destruction and spread of tumors
external surface: irregular
capsule: no
necrosis: yes
hemorrage: yes
What are the diagnostic techniques used to diagnose benign tumors?
imaging (X-ray, ultrasound, mammogram, CT, PET, MRI)
tests (blood test, BIOPSY)
scopy (colonoscopy, endoscopy)
What is the treatment for benign tumors?
treatment may not be needed
watch-and-wait
surgery
radiation therapy
What are the diagnostic techniques used to diagnose malignant tumors?
imaging (X-ray, ultrasound, mammogram, CT, PET, MRI)
tests (blood test, BIOPSY)
scopy (endoscopy, colonscopy)
What is the treatment for malignant tumors?
surgery (primary treatment)
chemotherapy
radiation therapy
-the above two can be done before surgery to reduce tumor
size
targeted therapy
immunotherapy
-the above two are not usually given before surgery
What is a CT scan?
computerized tomography
x-ray scan from different angles and computer-processed cross-sectional images
What is a PET scan?
positron emission tomography
uses a radioactive drug as a tracer, such as fluorodeoxyglucose
What is an MRI?
magnetic resonance image
uses magnetism, radio waves, and a computer to produce images
What is the main way to confirm diagnosis for most types of cancer?
biopsy
What can a biopsy help you figure out?
types of cells (benign or malignant)
grade level if malignant
biomarkers
What are the six hallmarks of malignant tumors?
self-sufficient growth signals
resistance to anti-growth signals
immortality
resistance to cell death
sustained angiogenesis
invasion and metastasis
What is the TNM system?
cancer staging system
T: size and extent of main tumor
N: number of nearby lymph nodes that have cancer
M: whether the cancer has metastatized
Explain T of the TNM system.
T: size + extent of primary tumor
-TX: main tumor cannot be measured
-T0: main tumor cannot be found
-T1, T2, T3, T4: refers to the size and/or extent of main tumor
Explain N of the TNM system.
N: number of nearby lymph nodes that have cancer
-NX: cancer in nearby lymph nodes cannot be measured
-N0: there is no cancer in nearby lymph nodes
-N1, N2, N3, N4: number and location of lymph nodes that
contain cancer
Explain M of the TNM system.
M: whether the cancer has metastasized
-MX: metastasis cannot be measured
-M0: cancer has not spread to other parts of the body
-M1: cancer has spread to other parts of the body
Explain each stage of cancer in accordance to the number staging system.
stage 1: relatively small and contained within original organ
stage 2: larger than stage 1, but has not started to spread into
surrounding tissue
stage 3: cancer is larger, has spread into surrounding tissues,
and cancer cells are in local lymph nodes
stage 4: spread from where it started to another body organ
Explain each grade within the cancer grading system.
GX: grade cannot be assessed (undetermined grade)
G1: well-differentiated (low grade)
G2: moderately differentiated (intermediate grade)
G3: poorly differentiated (high grade)
G4: undifferentiated (high grade)
True or false: higher grade is associated with greater prognosis
false
higher grade is associated with poorer prognosis
What are paraneoplastic syndromes? List some off.
rare disorders triggered by abnormal immune system response to cancer
-Cushings syndrome (hypercortisolism)
-hypercalcemia
-polycythemia
-venous thrombosis
-myasthenia gravis
What are the top 2 countries with highest cancer rates?
Australia
New Zealand
Higher GDP countries are associated with ____ incidence of cancer. Lower GDP countries are associated with ____ incidence of cancer.
higher
lower
What is the #1 cause of death in Canada?
cancer (28.2% of deaths)
What is the most prevalent form of cancer seen in women? What about men?
breast cancer
prostate cancer
Which provinces have the highest cancer prevalence? Which provinces have the lowest cancer prevalence?
highest: Atlantic region
lowest: Terriroties and Alberta
What are the most common forms of cancer in children?
liquid forms of cancer (leukemia) and brain cancer
Which cancer has the highest prevalence in both Canada and Saskatchewan?
lung cancer
True or false: genomic instability is usually associated with cancer
true
Where do new cancer cells form?
hypoxic regions
Describe new cancer cells.
non-proliferating
not sensitive to drugs
later recruited to proliferate
What are the exogenous and endogenous causes of carcinogenesis?
exogenous: chemical, physical, biologic (ex: viruses)
endogenous: oncogenes, tumor suppressor genes
What are examples of chemical carcinogens?
pesticides (PCBs, pentachlorophenol, etc)
polycyclic aromatic hydrocarbons
aromatic amines
nitroasmines
steroid hormones
inorganic compounds and metals
What does the process of chemical carcinogenesis look like?
initiation: mutations of normal cells
promotion: damage accumulated in cell
conversion: pre-neoplastic cell to cancerous cell
progression: invading local or distal sites
clonal expansion
What are examples of physical carcinogens?
UV light
X-rays
radioactive isotopes
nuclear bombs
nuclear power plant accidents
Explain the process of repair of DNA damaged by UV light. What would happen if this system fails?
under UV light, thymidine’s dimerize with a kink
this kink can be repaired and the cell will be healthy again
if the system fails, a cell with accumulated damage can undergo three possibilities:
-senescent cell (does nothing)
-apoptotic cell
-cancerous cell
What are examples of biological carcinogens?
alfatoxin (liver carcinogen)
-derived from fungus Aspergillus flavus
heliobacter pylori (gastric carcinogen)
schistosoma haematobium (urinary bladder carcinogen)
-parasiste
opisthorchis sinensis (bile duct carcinogen)
-Chinese liver fluke
human viral carcinogens (DNA and RNA oncogenic viruses)
What are examples of DNA and RNA oncogenic viruses?
DNA: HPV, EBV, Hep B
RNA: Human T-cell leukemia/lymphoma virus (HLTV-1)
How many types of HPV are there? How many are spread by genital skin contact? How many are oncogenic?
100
30
15
What is the normal function of oncogenes?
cell growth
cell transcription
gene transcription
migration
metastasis
What is the normal function of tumor suppressor genes?
DNA repair
cell cycle control
cell death
What are proto-oncogenes?
normal genes encoding normal proteins used in cell division
-growth factors
-growth factor receptors
-G proteins
-enzymes that produce secondary messengers
-genes that turn the production of these proteins on and off
What happens when a proto-oncogenes become mutated?
become oncogenes and contribute to cancer initiation and progression
What are the four ways that proto-oncogenes can be transformed into oncogenes?
point mutation (hyperactive protein in normal amounts)
gene amplification (normal protein greatly overproduced)
chromosomal rearrangement (regulatory DNA sequences causes normal protein to be overproduced)
insertion of viral oncogene (viral DNA inserted in host)
Oncogenes encode proteins needed for cell division, but what may they produce too much of?
too much of the protein
abnormal protein
protein that turns on by itself
protein that is made when not needed
protein that cannot turn cell division off
protein that should be made by a different cell
What are the tumor suppressor proteins?
cyclins
cyclin-dependent kinases
cyclin inhibitors
What is the role of tumor suppressors?
maintaining genomic integrity (DNA repair, chromosome segregation)
senses genomic damage
suppresses cell replication and growth when there is DNA damage
What is often the first mutation in a developing cancer?
tumor suppressors
What is the two-hit theory of cancer causation?
healthy cell:
-rare event occurs causing mutation in one chromosome (1st
hit)
-rare event occurs causing mutation in second chromosome
(2nd hit)
hereditary:
-carrying one mutation at birth
-rare event occurs causing mutation in other chromosome
-higher chance of developing cancer when first hit occurs from
birth
What will a tumor suppressor cell do if DNA is irreparable?
initiate cell death
What is metastasis? How does metastasis travel?
cancer spreads to a different part of the body
forms new tumor in other organs or tissue
travels in blood and lymph
What are common sites for metastasis?
liver
lung
brain
lymph nodes
bone
If breast cancer has spread to the bone, what would this be called?
bone metastasized breast cancer
