15 Minutes Immunohistochemistry Tutorial


Epithelial Markers


A.  Cytokeratins

   1.  Nonepithelial tumors expressing keratin

        a.  Mesothelioma

        b.  Meningioma

        c.  Synovial sarcoma

        d.  Epithelioid sarcoma

        e.  Chordoma

        f.  Some smooth muscle tumors

        g.  Rare melanomas, esthesioneuroblastomas, desmoplastic round cell tumors

B.  Epithelial Membrane Antigen (EMA)

C.  Carcinoembryonic Antigen (CEA)

D.  Leu M1 (CD15)

E.  Ber-Ep4

F.  Thyroid Transcription Factor (TTF-1)-nuclear

G.  Mesothelioma

H.  GCDFP-15 (gross cystic disease fluid protein-15)


Soft Tissue Tumor Markers


A.  Intermediate Filaments

   1.  Vimentin

        a.  Present in most mesenchymal tumors, including lymphomas, melanomas.

        b.  Ideal tissue control for immune reactivity.

        c.  May be expressed by some carcinomas (renal, lung).

            1)  Desmin

                a)  Most muscle tumors although may be negative up to 50% of leiomyosarcomas

                b)  Skeletal, cardiac, and smooth muscle are positive

B.  Myoid markers

   1.  Muscle-specific actin (MSA)

        a.  HHF-35 positive in skeletal, smooth and cardiac muscle and is most
            sensitive marker to identify muscle differentiation.

        b.  Some lymphomas and myofibroblastic lesions will stain.

   2.  Smooth muscle actin (SMA)

        a.  Not specific to smooth muscle, but useful and very sensitive.

   3.  Myoglobin

        a.  Most specific but not very sensitive.

        b.  Most often positive in rhabdoid differentiation.

   4.  Myo-D1

C.  Endothelial markers

   1.  Factor VIII

        a.  Very specific though not highly sensitive without trypsinization

        b.  May be negative to poorly differentiated angiosarcomas.

   2.  CD31

        a.  Most sensitive endothelial marker, platelets

        b.  Complete specificity

   3.  Ulex lectin

        a.  Useful, but positive in some carcinomas and epithelioid sarcoma

   4.  CD34

        a.  Best for endothelial cells of Kaposi's sarcoma

        b.  Positive in solitary fibrous tumor and DFSP dermatofibrosarcoma                   
            protuberans, GI stromal tumors, hemangiopericytomas, hematopoietic precursor      








CK7/CK20 Immunophenotype of Various Epithelial Tumors





CK7+ CK20 + Transitional Cell carcinoma

Pancreatic Carcinoma

Ovarian Mucinous Carcinoma

CK7+ CK20 - Non-Small Cell Adenocarcinoma of Lung

Bronchoalveolar Carcinoma of Lung

Breast Carcinoma, Ductal and Lobular Types

Ovarian Carcinoma Other than Mucinous CA Endometrial carcinoma

Malignant Mesothelioma

CK7 - CK20 + Colorectal Carcinoma

Merckel Cell carcinoma

CK7 - CK20 - Hepatocellular Carcinoma

Renal cell carcinoma

Prostatic Adenocarcinoma

Squamous Cell carcinoma of Lung

Small cell Neuroendocrine CA of Lung