38 Questions
What is a characteristic of traditional procedures that are not subjected to 'HOT SPOTS' and 'COLD SPOTS'?
Quick and simple
What is a disadvantage of traditional procedures?
Less sensitive
What is the purpose of a positive control in immunohistochemistry?
To ensure the section is known and proven to have the antigen in question
What is the purpose of a negative control in immunohistochemistry?
To omit the primary antibody from the staining schedule
What is an alternative to omitting the primary antibody in a negative control?
Replace the specific primary antibody with an Ig directed against an unrelated antigen
What is a possible reason for using fluorochromes in immunohistochemistry?
To visualize the antigen-antibody complex
What is the purpose of controls in immunohistochemistry?
To ensure the specificity and accuracy of the assay
What type of antibody is used in a negative control?
Ig directed against an unrelated antigen
What is the organ involvement in tumors marked with CK7?
Lungs, breast, uterus, and ovaries
What is the characteristic of transitional cell carcinoma?
Positive for both CK7 and CK20
Which of the following tumors is negative for CK7?
All of the above
What is the characteristic of tumors marked with CK20?
Negative for CK7
What is the primary function of Epithelial Membrane Antigen (EMA) in cancer diagnosis?
Helpful in determining the site of tumor adenocarcinoma of breast
What is the organ involvement in tumors marked with both CK7 and CK20?
Bladder and mucinous ovarian tumors
What type of protein is Epithelial Membrane Antigen (EMA)?
High molecular weight protein
What is the name of the technique used in tumor diagnosis?
Peroxidase antiperoxidase technique
Which of the following is NOT reactive to EMA?
Sarcoma
Which of the following tumors is negative for CK20?
Lung tumor
What is the result of EMA staining in hepatocellular carcinoma?
Non-reactive
What is the characteristic of squamous cell carcinoma?
Negative for both CK7 and CK20
What type of marker is EMA used to identify?
Epithelial marker
Which of the following tumors is EMA used to identify?
Adenocarcinoma of breast
What is the staining pattern of EMA in sarcoma?
Non-reactive
What is the main advantage of internal tissue control?
It eliminates the variable of tissue fixation between specimens and controls
What is the role of avidin-biotin complex in antigen detection?
It facilitates the binding of antibodies to antigens
What is the significance of EMA in cancer diagnosis?
It is used to determine the site of tumor adenocarcinoma
What is the characteristic of keratin as an epithelial tumor marker?
It is highly specific and sensitive to epithelial cells
What is the purpose of the unlabeled antibody technique?
To detect the target antigen in tissue samples
What is the main difference between internal tissue control and external tissue control?
Internal tissue control contains the target antigen, while external tissue control does not
What is the function of the enzyme immune complex in antigen detection?
It converts the substrate into a detectable product
Which isoenzyme is strongly evident for neural or neuroendocrine differentiation?
Neuron Specific Enolase
Which of the following is a feature of neuroendocrine carcinoma?
Presence of keratin and chromogranin
What is the function of chromogranin?
Found in neural secretory granules of endocrine tissue
What is the significance of a positive Grimiulis stain?
Indicates neuroendocrine differentiation
What is synaptophysin?
A 38kD transmembrane protein
What is the significance of a positive chromogranin and negative keratin?
Indicates paraganglioma
What is carcinoembryonic antigen?
An oncofetal antigen
What is the significance of synaptophysin in normal cells?
Found in neurons and neuroendocrine cells
Study Notes
Immunohistochemical Techniques
- Not subject to "HOT SPOTS" and "COLD SPOTS"
- Traditional procedures:
- Simple and quick
- However, disadvantages include less sensitivity
- Controls:
- A. Positive Control: Section known to have the antigen in question
- B. Negative Control: Omit primary antibody or replace with Ig directed against unrelated antigen
- C. Internal Tissue Control: "BUILT IN" control, eliminates tissue fixation variable between specimens and controls
Indirect and Unlabeled Antibody Techniques
- Avidin-Biotin Complex (ABC) Technique:
- Eliminates tissue fixation variable between specimens and controls
- Contains target antigen but not in tissue elements under investigation
- Soluble Enzyme Immune Complex Technique:
- Uses Streptomycin
- Substrate requires 7 days
Epithelial Tumor Markers
-
- Keratin:
- Highly sensitive marker for epithelial cells and epithelial tumors
- CK7: positive in lungs, breast, uterus, and ovaries, negative for CK20
- CK20: positive in colon and stomach, negative for CK7
- Both CK7 and CK20 positive in Transitional cell carcinoma, Bladder and mucinous ovarian tumor
-
- Epithelial Membrane Antigen (EMA):
- High molecular weight protein
- Helpful in determining site of tumor origin
- Adenocarcinoma of breast: EMA positive
Neuroendocrine Markers
-
- Neuron Specific Enolase (NSE):
- Isoenzyme indicative of neural or neuroendocrine differentiation
-
- Chromogranin:
- Found in neural secretory granules of endocrine tissue
- Positive neuroendocrine differentiation = Grimelius stain
-
- Synaptophysin:
- 38kD transmembrane protein
- Normal in neurons and neuroendocrine cells
- Confirms neuroendocrine differentiation
Germ Cell Tumor Markers
- 1.Carcinoembryonic Antigen (CEA):
- Oncofetal antigen
Test your knowledge on immunohistochemistry procedures, including traditional methods and fluorochromes. Assess your understanding of primary and secondary antibodies. Take this quiz to evaluate your skills in biology laboratory techniques.
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