Sources/Clones
Biodesign, Biogenesis (3.14.A3), Biogenex (115D8), Immunotech (KC4, 1.10.F3, 3.14.A3), Novocastra (1.10.F3, 3.14.A3) and Unipath (1.10.F3, 3.14.A3).
Fixation/Preparation
Both antibody clones available are immunoreactive in fixed, paraffin-embedded section. HIER enhances staining.
Background
The human milk fat globule (HMFG) is a complex secretory product of mammary epithelium. HMFG is a relatively pure cell membrane product and is partially covered by a typical unit membrane that is extruded from the luminal surface of breast epithelial cells by reverse pinocytosis (Freudenstein et al, 1979). Besides the covering unit membrane, filamentous membrane structures, including cytoplasm-associated glycoproteins, can be detected on the inner coat of the HMFG. Similar to the plasma membrane, HMFG expresses considerable enzymatic activity, including that of glucose-6-phosphate dehydrogenase, acid and alkaline phosphatases, magnesium-dependent ATPase, aldolase, galactosyl transferase and xanthine oxidase.
A heterogeneous population of HMFG proteins can be recovered from the aqueous phase of skimmed milk following extraction in chloroform and methanol. This pool of solubilized glycoproteins is derived from a human epithelial membrane and referred to as epithelial membrane antigen (EMA). HMFG is thus very similar to EMA and from a practical standpoint, antibodies to these proteins have very similar patterns of immunoreactivity. A polyclonal antibody was initially shown to react with EMA and related HMFG protein determinants in formalin-fixed, paraffin-embedded sections and has been extensively used in normal and neoplastic tissues (Heyderman et al, 1979; Sloane et al, 1983).
Applications
The expression of HMFG is heterogeneous in both normal and neoplastic epithelium and its distribution bears no relationship to cellular morphology. The heterogeneity appears to be the result of normal cellular glycosylation patterns and appears to be reproducible in clonal proliferations of all epithelial cells (Edwards, 1985). HMFG proteins are widely distributed in secretory epithelia and their corresponding tumors and fetal anlage. These include sweat glands, sebaceous, apocrine and salivary glands, epithelium of the intestines, bile ducts, endometrium and endosalpinx, pulmonary alveolar cells and exocrine pancreas. HMFG is also expressed by some non-secretory epithelia such as the distal and collecting tubules of the kidney, and urothelium. Syncytiotrophoblasts, glandular cells of the endocervix, prostate, epidydimis, rete testes and thyroid may also be reactive for HMFG. Generally, hepatocytes and proximal tubular epithelia are negative.
Comments
We employ anti-EMA in preference to anti-HMFG but do not use it as a generic marker of epithelial differentiation as some mesenchymal cells such as mesothelial cells, plasma cells and their corresponding tumors may express HMFG/EMA. In addition, soft tissue tumors such as synovial sarcoma, epithelioid sarcoma, peripheral nerve sheath tumor, smooth muscle tumor, rhabdomyosarcoma, chordoma, ependymoma and choroid plexus tumors may express HMFG/EMA.
References
•Edwards PAW 1985 Heterogeneous expression of cell-surface antigens in normal epithelia and their tumours, revealed by monoclonal antibodies. British Journal of Cancer 51:149-160.
•Freudenstein C, Keenan TW, Eigel WN et al 1979. Preparation and characterization of the inner coat meterial associated with fat globule membranes from bovine and human milk. Experimental Cell Research 118:277-294.
•Heyderman E, Steele K, Omerod MG 1979 A new antigen on the epithelial membrane: Its immunoperoxidase localisation in normal and neoplastic tissue. Journal of Clinical Pathology 32: 35-39.
•Sloane JP, Hughes F, Ormerod MG 1983 An assessment of the value of epithelial membrane antigen and other epithelial markers in solving diagnostic problems in tumour histology. Histochemistry Journal 15:645-654.
Bibliografía
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
Biodesign, Biogenesis (3.14.A3), Biogenex (115D8), Immunotech (KC4, 1.10.F3, 3.14.A3), Novocastra (1.10.F3, 3.14.A3) and Unipath (1.10.F3, 3.14.A3).
Fixation/Preparation
Both antibody clones available are immunoreactive in fixed, paraffin-embedded section. HIER enhances staining.
Background
The human milk fat globule (HMFG) is a complex secretory product of mammary epithelium. HMFG is a relatively pure cell membrane product and is partially covered by a typical unit membrane that is extruded from the luminal surface of breast epithelial cells by reverse pinocytosis (Freudenstein et al, 1979). Besides the covering unit membrane, filamentous membrane structures, including cytoplasm-associated glycoproteins, can be detected on the inner coat of the HMFG. Similar to the plasma membrane, HMFG expresses considerable enzymatic activity, including that of glucose-6-phosphate dehydrogenase, acid and alkaline phosphatases, magnesium-dependent ATPase, aldolase, galactosyl transferase and xanthine oxidase.
A heterogeneous population of HMFG proteins can be recovered from the aqueous phase of skimmed milk following extraction in chloroform and methanol. This pool of solubilized glycoproteins is derived from a human epithelial membrane and referred to as epithelial membrane antigen (EMA). HMFG is thus very similar to EMA and from a practical standpoint, antibodies to these proteins have very similar patterns of immunoreactivity. A polyclonal antibody was initially shown to react with EMA and related HMFG protein determinants in formalin-fixed, paraffin-embedded sections and has been extensively used in normal and neoplastic tissues (Heyderman et al, 1979; Sloane et al, 1983).
Applications
The expression of HMFG is heterogeneous in both normal and neoplastic epithelium and its distribution bears no relationship to cellular morphology. The heterogeneity appears to be the result of normal cellular glycosylation patterns and appears to be reproducible in clonal proliferations of all epithelial cells (Edwards, 1985). HMFG proteins are widely distributed in secretory epithelia and their corresponding tumors and fetal anlage. These include sweat glands, sebaceous, apocrine and salivary glands, epithelium of the intestines, bile ducts, endometrium and endosalpinx, pulmonary alveolar cells and exocrine pancreas. HMFG is also expressed by some non-secretory epithelia such as the distal and collecting tubules of the kidney, and urothelium. Syncytiotrophoblasts, glandular cells of the endocervix, prostate, epidydimis, rete testes and thyroid may also be reactive for HMFG. Generally, hepatocytes and proximal tubular epithelia are negative.
Comments
We employ anti-EMA in preference to anti-HMFG but do not use it as a generic marker of epithelial differentiation as some mesenchymal cells such as mesothelial cells, plasma cells and their corresponding tumors may express HMFG/EMA. In addition, soft tissue tumors such as synovial sarcoma, epithelioid sarcoma, peripheral nerve sheath tumor, smooth muscle tumor, rhabdomyosarcoma, chordoma, ependymoma and choroid plexus tumors may express HMFG/EMA.
References
•Edwards PAW 1985 Heterogeneous expression of cell-surface antigens in normal epithelia and their tumours, revealed by monoclonal antibodies. British Journal of Cancer 51:149-160.
•Freudenstein C, Keenan TW, Eigel WN et al 1979. Preparation and characterization of the inner coat meterial associated with fat globule membranes from bovine and human milk. Experimental Cell Research 118:277-294.
•Heyderman E, Steele K, Omerod MG 1979 A new antigen on the epithelial membrane: Its immunoperoxidase localisation in normal and neoplastic tissue. Journal of Clinical Pathology 32: 35-39.
•Sloane JP, Hughes F, Ormerod MG 1983 An assessment of the value of epithelial membrane antigen and other epithelial markers in solving diagnostic problems in tumour histology. Histochemistry Journal 15:645-654.
Bibliografía
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
