Immunohistochemistry

What is Immunohistochemistry (IHC)?

Immunohistochemistry is a laboratory technique used in pathology to detect specific antigens (proteins) in tissue samples using antibodies. This method plays a vital role in diagnosing diseases, particularly in tumor diagnostics and cancer subtype detection.

By combining histopathology and immunology, IHC allows pathologists to:

• Identify molecular markers of diseases.
• Assess the presence and extent of tumors.
• Determine appropriate treatment strategies based on cellular markers.

In Turkey’s pathology labs, IHC is widely used for both clinical diagnostics and research, ensuring accurate results through advanced technology and highly trained professionals.

Overview of IHC Techniques

Immunohistochemistry employs several methodologies to visualize antigen-antibody interactions:

1. Direct Method: A labeled antibody binds directly to the target antigen.
2. Indirect Method: An unlabeled primary antibody binds to the antigen, followed by a labeled secondary antibody for visualization.
3. Polymer-Based Techniques: Enhance signal detection, improving the clarity and sensitivity of results.

Role of IHC in Cancer Diagnostics

IHC is indispensable in hematology oncology diagnostics, aiding in:

• Identifying cancer origins when primary tumors are unknown.
• Differentiating between similar cancer types (e.g., lymphoma vs. carcinoma).
• Detecting specific biomarkers critical for targeted therapies.

Key Applications in Pathology and Research

Beyond cancer diagnosis, IHC is used to study autoimmune diseases, infectious conditions, and neurological disorders. In research, it helps explore disease mechanisms and test therapeutic interventions.

How is Immunohistochemistry Performed?

The IHC process is meticulous, requiring precision at every step to ensure reliable results.

Sample Preparation: Fixation and Paraffin Embedding

1. Fixation: Tissue samples are preserved in formalin to maintain cellular integrity.
2. Embedding: The fixed tissue is embedded in paraffin wax, creating stable blocks for thin slicing.

Antibody Binding and Staining Techniques

• Primary Antibodies: Target specific antigens in the sample.
• Secondary Antibodies: Amplify the signal for clearer detection.
• Chromogenic Staining: Produces a visible color change at antigen sites.
• Fluorescent Staining: Offers high sensitivity for detecting rare markers.

Analysis and Interpretation of Results

After staining, slides are examined under a microscope. Pathologists analyze:

• The location and intensity of staining.
• Patterns indicating the presence or absence of specific proteins.
  This detailed analysis helps in confirming diagnoses and guiding treatment plans.