Immunohistochemistry Techniques and Tumor Markers

Histochemistry

Combines biochemistry and histology to study tissues.

Immunology

Study of the immune system and responses.

Immunohistochemistry (IHC)

Localization of antigens in tissues using antibodies.

Fixation

Prevents elution, degradation, and modification of samples.

Formaldehyde

Preferred fixative for immunohistochemistry procedures.

Antigen Retrieval

Process to unmask antigens for antibody binding.

Blocking

Prevents non-specific binding of antibodies.

Primary Antibodies

Antibodies that bind directly to target antigens.

Direct Method

Uses primary antibodies for antigen detection.

Indirect Method

Uses secondary antibodies to amplify signal.

Detection Method

Techniques to visualize antibody-antigen complexes.

Keratin

Marker for epithelial cells in carcinomas.

EMA

Positive in adenocarcinomas of breast, lung, kidneys.

CEA

Marker for gastrointestinal tract and breast carcinomas.

TTF-1

Positive in thyroid and lung neuroendocrine tumors.

PSA

Marker for diagnosing prostatic adenocarcinoma.

Actin

Contractile protein found in muscle tissues.

Vimentin

Marker for mesenchymal cells and sarcomas.

Desmin

Specific for myogenic tumors like leiomyoma.

GFAP

Marker for glial cells in the CNS.

Neurofilament

Expressed in neural origin cells.

S100 Protein

Calcium-binding protein in various cell types.

HCG

Marker for choriocarcinoma from placental cells.

AFP

Identifies endodermal sinus tumors and hepatocellular carcinomas.

PLAP

Marker for germ cell tumors, especially seminomas.

Myogenic Tumors

Characterized by muscle-specific markers like actin.

Fibrohistiocytic Tumors

Identified using CD68 and proteolytic enzymes.

Vascular Tumors

Markers include Factor VIII and CD31.

Melanomas

Diagnosed using S100, HMB-45, and Melan-A.

Lymphomas

Identified using LCA and specific T/B-cell markers.

Neuron-Specific Enolase (NSE)

Indicates neural differentiation in tissues.

Chromogranin

Marker of neuroendocrine differentiation.

Synaptophysin

Associated with presynaptic vesicles in neurons.

Ki67

Marker for cell proliferation using MIB-1.

PCNA

Associated with cell proliferation in tissues.