Laboratory Diagnosis of Cancer (M) Flashcards
What are the methods for lab dx of CA?
1) Morphologic methods
a. Cytology
b. Tissue biopsy
c. Immunohistochemistry (IHC)
d. Flow cytometry
2) Biochemical assays
a. Tumor markers
3) Molecular dx
a. Polymerase chain reaction (PCR)
b. Fluorescence in-situ hybridization (FISH)
4) Molecular profiling
a. DNA-microarray
What are the methods under cytology?
1) Exfoliative cytology
a. Cervical Pap’s smear
b. Washings / Brushings
2) Fine needle aspiration biopsy (FNAB)
a. Fluids
i. Pleural
ii. Peritoneal
iii. CSF
iv. Urine
What are the methods under tissue biopsy?
1) Incision biopsy
2) Punch biopsy
3) Core biopsy
4) Cone biopsy
5) Excision biopsy
6) Tissue resection
7) Frozen section dx
What is the characteristic IHC?
It is the basic battery to differentiate tumors
What are the tumor markers under IHC?
1) Cytokeratin
2) Vimentin
3) Leukocyte common antigen (LCA)
4) S-100 / NSE
What is flow cytometry?
It is a rapid and dynamic method of correlated multiparameter, single cell analysis
What are flow cytometers?
These are instruments that determine the characteristics of the cells in a complex cell mixture
What is the action of flow cytometry?
It is designed to enhance microscopic analysis of individual cells using fluorescent substrates and probes
Flow cytometry is originally developed for what purpose?
For the purpose of sorting cells or fluorescence-activated cell sorting (FACS)
What is the mechanism (/ principle / method) of flow cytometry?
1) A suspension of cells (or other biological
particles), either directly or indirectly labeled with
1 or more flourescent probes, is led in a stream
past an illumination and light detection system
2) The cells traverse the illumination spot one by one
3) When the jet stream intersects the laser beam,
fluorescent excitation occurs
4) A microscope objective projects the scatter and
fluorescence light that bounces off the cells to a set
of photomultipliers
5) Temporal, spatial and chromatic filters eliminate
background light and separate the signals from
different fluorophores
6) Digital acquisition electronics measure the
intensity of the light pulses
7) Each cell is measured for light scatter signals and
the presence or absence of fluorescence are
subsequently classified
8) A cell sorter adds a sorting mechanism to a flow
cytometer so that the cells can be separated after
they have been measured and classified
How cell sorting works (/ what is the method of how cell sorting works)?
1) Cells are suspended in a stream
2) Laser beams excite cell fluorescence
3) Signals are measured
4) Stream breaks into drops
5) Drops with cells are charged
6) Electrostatic field deflects drops
7) Drops with cells are collected
8) High speed cell sorters identify and select fluorescent particles at a rate of ~25,000 per second or 100,000,000 per hour
What must be the characteristic of selected fluorochrome rgnts?
Those selected must be suitable for excitation by 488 nm light
What are the exs of fluorochrome rgnts?
1) Fluorescein isothiocyanate (FITC)
2) Phycoerythrin (PE)
3) Propidium iodide (PI)
4) 7-amino-actinomycin D (7AAD)
5) Peridin-chlorophyl-A-protein (PerCP)
6) Dimers of thiazole orange (TOTO-1)
What are the most commonly analyzed clinical materials (/ sxs) in flow cytometry?
1) Blood
2) Bone marrow aspirates
3) Lymph node suspensions
What is the most frequently recommended technique used for sx preparation (for flow cytometry)?
Whole blood lysis
What is the recommended for preparing sxs for FC immunophenotyping of leukemias and lymphomas?
Whole blood lysis
How is whole blood lysis (in terms of sx preparation for flow cytometry) done?
1) Incubation of a fixed volume of anticoagulated whole blood (or bone marrow) with one or more directly conjugated monoclonal antibodies followed by red blood cell lysis, washing, fixation in formaldehyde, and flow cytometric analysis
2) Gating is used for identifying cells/ particles of interest in a mixed population, e.g. non-lysed RBCs, platelets, debris
What are the advantages of doing whole blood lysis (in terms of sx preparation for flow cytometry)?
1) Fewer preparation steps
2) Less sx handling
3) Lower likelihood of differential cell loss
What are the uses of flow cytometry?
1) Immunophenotyping for non-malignant disease
2) Characterization of lymphoid and myeloid malignancies
3) Hematopoietic stem cell enumeration
4) Red blood cell characterization
5) Platelet evaluation
6) Cell function testing
7) Cell cycle and apoptosis assessment
8) Human leukocyte antigen (HLA) typing
What are the clinical applications of flow cytometry?
1) Monitoring AIDS pts
2) Immunophenotyping leukemia and lymphomas and monitoring residual disease
3) Determining CD34 counts for hematopoietic reconstitution
4) Monitoring organ transplant pts for rejection
5) Reticulocyte counts
6) Dx of paroxysmal nocturnal hemoglobinuria (PNH)
7) DNA analysis of S-phase fraction of solid tumors
What are the characteristics of tumor markers (as used in biochemical assays)?
1) Nonspecific due to low sensitivity and specificity
2) Very effective in tumor staging, monitoring, and detecting recurrence
What are the FDA approved kits in connection w/ tumor markers (w/c are being used in biochemical assays)?
1) Alpha fetoprotein (AFP)
2) Carcinoembryonic antigen (CEA)
3) ER
4) Cancer antigen (CA) 125
5) Prostate specific antigen (PSA)
What are the 2 major processes involved in growth (for tumor markers)?
1) Proliferation
2) Differentiation
What is the characteristic of proliferation and differentiation?
Normally, these are well-regulated and under rigid control
What is the effect of loss of regulation (or / in proliferation and differentiation)?
Loss of the regulation increases the risk of these normal cells turning into tumor cells
Is there a tumor-specific marker that is developed and well-studied enough to be widely used in clinical practice?
None yet
True or False
Any cell product may be used as a marker as long as it is related to any event during tumor formation
True
The clinical value of any given tumor marker will depend on what?
On the intended clinical use and the specificity and sensitivity of the tumor marker
What are the types of tumor markers (in terms of identification)?
1) Associated w/ cell proliferation
2) Related to cell differentiation
3) Related to metastasis
4) Related to other tumor-associated events
5) Related to malignant transformation
6) Inherited mutations
What are the exs of tumor markers that are associated w/ cell proliferation?
1) Hormones
a. HCG
2) Serum proteins
3) Enzymes
4) Metabolites
What are the characteristics of tumor markers w/c are associated w/ cell proliferation?
1) Their lvls are increased
2) These are more useful in monitoring pts during treatment
Why are the lvls of tumor markers w/c are associated w/ cell proliferation increased?
Due to high proliferation rate of the cells
True or False
Benign diseases may also involve elevated lvls of tumor markers (w/c are associated w/ cell proliferation), hence, they are not suitable for screening of for CA dx
True
What is the ex of tumor markers w/c are related to cell differentiation?
Most are carcinoembryonic proteins
What are the characteristics of tumor markers w/c are related to cell differentiation?
1) Measurement rely on immunoassay because their conc. in the serum is in nannogram/mL lvls
2) Correlates well w/ tumor activity and can be used to predict px
3) Generally, they are not suitable for screening because:
a. Polyclonal Ab directed against these proteins often cross-react w/ normal proteins
b. Do not appear sufficiently early in the blood from CA pts
What are the uses of tumor markers w/c are related to cell differentiation?
1) These are used as adjunct in CA dx
2) These are very useful for monitoring success of treatment
3) These are very useful for detecting recurrence
What are the concepts related to tumor markers w/c are related to metastasis?
1) Several steps are involved in metastasis
2) All cell products released during these steps are candidates to be a tumor marker
3) However, their measurement is still limited to tumor tissue / tumor cell cytosols
What are the tumor markers w/c are related to other tumor-associated events?
These are glycosyltransferases w/ altered activities
What are the exs of tumor markers w/c are related to other tumor-associated events?
1) Blood grp substances
2) Mucins
a. CA 19-9
3) α-fetoprotein / alpha fetoprotein (AFP) w/ additional fucose
What is the characteristic of tumor markers w/c are related to other tumor-associated events?
These are tumor markers w/ altered enzymatic activities
Why do tumor markers w/c are related to other tumor-associated events has altered enzymatic activities?
Due to tumor formation
In relation w/ tumor markers w/c are related to malignant transformation, what are the genes that play a major role in cell transformation?
Oncogenes
In relation w/ tumor markers w/c are related to malignant transformation, what is the mechanism of oncogenes that have lost their regulatory constraints on their activity?
Oncogenes that have lost their regulatory constraints on their activity may produce oncoproteins w/c have been used for px
What are the exs of tumor markers w/c are related to malignant transformation?
1) c-erbB-2 protein
2) p185 protein
True or False
In relation w/ tumor markers w/c are related to malignant transformation, since malignant transformation is a sp event in carcinogenesis, any cell product associated w/ this has the potential to be a more sp tumor marker
True
What is the principle of inherited mutations?
Grp of suppressor genes that underwent mutations resulting to the production of inactive gene products (protein)
What is the characteristic of inherited mutations?
These are usually found in families w/ increase risk of CA
What are the exs of tumor markers w/c are related in inherited mutations?
1) p53
2) BRCA 1
3) BRCA 2
What is the percentage of probability of occurrence of BRCA 1 (in relation w/ inherited mutations)?
50% of cases of inherited breast CA
What is the status of risk of occurrence of BRCA 2 (in relation w/ inherited mutations)?
Increased risk of breast CA in males
What are the uses of tumor markers w/c are related w/ inherited mutations?
These are useful for screening and identification of families and individuals at high risk
What are the clinical applications of tumor markers?
1) Screening
2) Dx
3) Monitoring treatment
4) Detection of recurrence
5) For px
True or False
In terms of clinical application of tumor markers, clinical utility of a tumor marker does not depend totally on its specificity and sensitivity
False, because clinical utility of a tumor marker depends almost totally on its specificity and sensitivity
Is screening using tumor markers recommended in asymptomatic population? Why or why not?
No, due to low sensitivity, specificity, and prevalence of CA
What are the exceptions related to screening (since screening using tumor markers is not recommended in asymptomatic population)?
1) Serum AFP to screen for primary hepatoma
2) CA 125 to screen for ovarian CA in women
3) PSA together w/ DRE to screen for prostate CA
Are most tumor markers used in the dx of CA? Why or why not?
No, the use of most tumor markers in the dx of CA is discouraged due to their low specificity and sensitivity
What is the effect if tumor markers are used for dx of CA?
There will be a fail to distinguish malignant from benign disease
What are the schemes used to improve the diagnostic specificity of many tumor markers?
1) Use of multiple marker
2) Measurement of velocity and density in cases of prostate CA
What is 1 of the 2 most useful application of tumor markers?
Monitoring treatment
What is the effect of monitoring treatment brought by tumor markers?
It reflects well the success of surgery / efficacy of chemotherapy
In terms of monitoring treatment (brought by tumor markers), detecting elevated lvls of tumor markers after surgery indicates what?
1) Incomplete removal
2) Recurrence
3) Metastasis
What is the 2nd most useful application of tumor markers?
Detection of recurrence
True or False
Ease of drawing blood and the sensitivity of tumor marker tests make the noninvasive monitoring process widely accepted (in connection w/ detection of recurrence brought by tumor markers)
True
True or False
The specificity of tumor markers does not present a problem for this application (in relation w/ detection of recurrence brought by tumor markers)
True
True or False
Assessment of tumor aggressiveness and px does not help in the development of a proper therapy (in relation w/ px brought by tumor markers)
False, because assessment of tumor aggressiveness and px helps in the development of a proper therapy
In terms of px, what happens to most tumor markers when the tumor metastasizes?
Most tumor markers become increasingly elevated when the tumor metastasizes
What is the characteristic of tumor markers w/c are highly associated w/ metastasis?
These are better markers for predicting px, but these tumor markers are still measured in tumor tissues and tissue cytosols
What tumor marker should be used for px?
c-erbB-2 protein
What are the types of assay (/ assay design)?
1) Competitive binding (/ competitive ELISA)
2) Sandwich format (/ sandwich ELISA)
What is the mechanism of competitive binding?
Quantify many circulating tumor markers in the nano- and picogram/mL conc. ranges
What is the principle of competitive binding?
It involves competition between a fixed amt of radioactively-labeled Ag and Ag in the sx for a limited amt of Ab
In relation w/ competitive binding, any substances interfering w/ Ag-Ab binding can what?
Can falsely elevate the value
What is the characteristic of sandwich format (/ ELISA using sandwich format)?
It has become the most popular method for tumor marker quantification
What is the principle (/ method) of sandwich format?
1) A sp Ab is adsorbed in a solid phase, then a solution of Ag is added
2) After sufficient incubation and washing, an enzyme-labeled Ab is added to the solid phase
3) After washing unbound labeled-Ab, the remaining solid phase contains the Ag “sandwiched” between the Ab adsorbed to the solid phase and the labeled Ab
What is the problem that may exist in sandwich format?
Hook effects
In terms of comparison between monoclonal and polyclonal Ab, what Ab allows a more detailed immunochemical and molecular analysis of tumor markers?
Monoclonal Abs
What are the effects that were eliminated if monoclonal Ab is combined w/ the solid phase of the sandwich test design?
1) Poor reproducibility
2) Lot-to-lot variations
3) Poor specificity
4) Poor cross-reactivity
True or False
Whenever a monoclonal Ab is available, its use is recommended (in relation w/ the comparison between monoclonal and polyclonal Ab)
True
What are the associated CAs of the given tumor marker?
Given tumor marker: AFP
1) Hepatocellular carcinoma
2) Nonseminomatous testicular germ-cell tumors
What are the associated CAs of the given tumor marker?
Given tumor marker: β- human chorionic gonadotropin (hCG)
1) Trophoblastic tumors
2) Choriocarcinoma
What is the associated CA of the given tumor marker?
Given tumor marker: Calcitonin
Medullary carcinoma of the thyroid
What are the associated CAs of the given tumor marker?
Given tumor marker: CEA
Carcinoma of the:
1) Lung
2) Pancreas
3) Stomach
4) Breast
5) Colon
What is the associated CA of the given tumor marker?
Given tumor marker: CA-125
Ovarian CA
What is the associated CA of the given tumor marker?
Given tumor marker: CA 19-9
Pancreatic CA
What is the associated CA of the given tumor marker?
Given tumor marker: Placental alkaline phosphatase (PLAP)
Seminoma
What is the associated CA of the given tumor marker?
Given tumor marker: Prostatic acid phosphatase
Prostate CA
What is the associated CA of the given tumor marker?
Given tumor marker: PSA
Prostate CA
What are the associated CAs of the given tumor marker?
Given tumor marker: S-100
1) Melanoma
2) Neural-derived tumors
3) Astrocytoma
What is the associated CA of the given tumor marker?
Given tumor marker: Tartrate- resistant acid phosphatase (TRAP)
Hairy cell leukemia
