Biology: Immunohistochemistry Procedures Quiz

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Questions and Answers

What is a characteristic of traditional procedures that are not subjected to 'HOT SPOTS' and 'COLD SPOTS'?

Subject to hot spots and cold spots
More sensitive
Less sensitive
Quick and simple (correct)

What is a disadvantage of traditional procedures?

More sensitive
Require more fluorochromes
Quick and simple
Less sensitive (correct)

What is the purpose of a positive control in immunohistochemistry?

To ensure the section is known and proven to have the antigen in question (correct)
To omit the primary antibody from the staining schedule
To use a different fluorochrome
To replace the specific primary antibody with an Ig directed against an unrelated antigen

What is the purpose of a negative control in immunohistochemistry?

To omit the primary antibody from the staining schedule (D) Signup and view all the answers

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 (B) Signup and view all the answers

What is a possible reason for using fluorochromes in immunohistochemistry?

To visualize the antigen-antibody complex (D) Signup and view all the answers

What is the purpose of controls in immunohistochemistry?

To ensure the specificity and accuracy of the assay (B) Signup and view all the answers

What type of antibody is used in a negative control?

Ig directed against an unrelated antigen (C) Signup and view all the answers

What is the organ involvement in tumors marked with CK7?

Lungs, breast, uterus, and ovaries (A) Signup and view all the answers

What is the characteristic of transitional cell carcinoma?

Positive for both CK7 and CK20 (A) Signup and view all the answers

Which of the following tumors is negative for CK7?

All of the above (D) Signup and view all the answers

What is the characteristic of tumors marked with CK20?

Negative for CK7 (D) Signup and view all the answers

What is the primary function of Epithelial Membrane Antigen (EMA) in cancer diagnosis?

Helpful in determining the site of tumor adenocarcinoma of breast (A) Signup and view all the answers

What is the organ involvement in tumors marked with both CK7 and CK20?

Bladder and mucinous ovarian tumors (B) Signup and view all the answers

What type of protein is Epithelial Membrane Antigen (EMA)?

High molecular weight protein (C) Signup and view all the answers

What is the name of the technique used in tumor diagnosis?

Peroxidase antiperoxidase technique (D) Signup and view all the answers

Which of the following is NOT reactive to EMA?

Sarcoma (D) Signup and view all the answers

Which of the following tumors is negative for CK20?

Lung tumor (A) Signup and view all the answers

What is the result of EMA staining in hepatocellular carcinoma?

Non-reactive (B) Signup and view all the answers

What is the characteristic of squamous cell carcinoma?

Negative for both CK7 and CK20 (D) Signup and view all the answers

What type of marker is EMA used to identify?

Epithelial marker (D) Signup and view all the answers

Which of the following tumors is EMA used to identify?

Adenocarcinoma of breast (B) Signup and view all the answers

What is the staining pattern of EMA in sarcoma?

Non-reactive (D) Signup and view all the answers

What is the main advantage of internal tissue control?

It eliminates the variable of tissue fixation between specimens and controls (D) Signup and view all the answers

What is the role of avidin-biotin complex in antigen detection?

It facilitates the binding of antibodies to antigens (B) Signup and view all the answers

What is the significance of EMA in cancer diagnosis?

It is used to determine the site of tumor adenocarcinoma (B) Signup and view all the answers

What is the characteristic of keratin as an epithelial tumor marker?

It is highly specific and sensitive to epithelial cells (C) Signup and view all the answers

What is the purpose of the unlabeled antibody technique?

To detect the target antigen in tissue samples (A) Signup and view all the answers

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 (B) Signup and view all the answers

What is the function of the enzyme immune complex in antigen detection?

It converts the substrate into a detectable product (C) Signup and view all the answers

Which isoenzyme is strongly evident for neural or neuroendocrine differentiation?

Neuron Specific Enolase (B) Signup and view all the answers

Which of the following is a feature of neuroendocrine carcinoma?

Presence of keratin and chromogranin (A) Signup and view all the answers

What is the function of chromogranin?

Found in neural secretory granules of endocrine tissue (A) Signup and view all the answers

What is the significance of a positive Grimiulis stain?

Indicates neuroendocrine differentiation (B) Signup and view all the answers

What is synaptophysin?

A 38kD transmembrane protein (A) Signup and view all the answers

What is the significance of a positive chromogranin and negative keratin?

Indicates paraganglioma (D) Signup and view all the answers

What is carcinoembryonic antigen?

An oncofetal antigen (C) Signup and view all the answers

What is the significance of synaptophysin in normal cells?

Found in neurons and neuroendocrine cells (A) Signup and view all the answers

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

1. 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
1. Epithelial Membrane Antigen (EMA):
- High molecular weight protein
- Helpful in determining site of tumor origin
- Adenocarcinoma of breast: EMA positive

Neuroendocrine Markers

1. Neuron Specific Enolase (NSE):
- Isoenzyme indicative of neural or neuroendocrine differentiation
1. Chromogranin:
- Found in neural secretory granules of endocrine tissue
- Positive neuroendocrine differentiation = Grimelius stain
1. Synaptophysin:
- 38kD transmembrane protein
- Normal in neurons and neuroendocrine cells
- Confirms neuroendocrine differentiation

Germ Cell Tumor Markers

1.Carcinoembryonic Antigen (CEA):
- Oncofetal antigen

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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.