الفهرس 
materials and methodsOnly 14 pages are availabe for public view
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Abstract
The skin of head and neck amounts to less than 10% of the body surface area, yet a large majority of all cutaneous tumours occur in this area.
Immunohistochemical analysis of skin tumours of the head and neck is a matter of great complexity and have added exciting new dimensions to diagnostic dermatopathology. The advent of monoclonal antibodies had allowed the production of numerous new reagents specific for a variety of antigens including those expressed by the epithelium.
The aim of this work, is to try to detect the value of broad spectrum keratin, EMA, 5100 protein monoclonal and CEA polyclonal antibodies in diagnosis of malignant skin tumours and their value in undiffern-tiated carcinoma of head and neck. Also, the aim of this Work is to identify the cell of origin of cutaneous tumours.
In the present work, 60 Egyptian patients with different epidermal and epidermal appendageal carcinoma of ,n neck has been selected and examined immuno-histochemically.
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Monoclonal antibodies distribution in hyper-keratotic, benign and premalignant epithelial lesions show some difference than that shown in normal epidermis and in malignant tumours, and therefore these lesions need more study. This may give a useful value in early detection of carcinoma from knowing the changes in their antigens and that is because there is no specific tumour marker for early detection of malignancy.
It is found that broad spectrum keratin, EMA, and CEA antibodies are markers of keratinocyte diffe-ler Adt:c: and maturation. Keratin is a useful marker for epithelial cells regardless of its site, and because there is different distribution and locali-
J zation of keratin proteins with different molecular weights in various layers of the epidermis,
so that,
keratinocytes from basal cell layer to cornified
—r—j cells demonstrate a regular profile which may help
---] in identification of the site of any isolated keratino-
cytes, whereas malignant transformed cells might display an irregular distribution of keratin and so that it might be prepared different monoclonal antikeratin antibodies from each layer and from each tumour to help to know the cell of origin by judicious
flplications cf selected antibodies that react only a rell-a--tined group of keratin molecules which distinguish the cell of origin of any tumour.
EMA monoclonal antibody, is a good marker for sebaceous and meibomian carcinomas and have a practical value as sebaceous carcinomas was poorly recognized clinically and fat stains are not possible after Wax embedding and dehydration of tumours and the EMA antibody reaction has been observed to exist even in single invaded malignant cells that would go unrecognized in Hx. and E. stained sections. This enables pathologist for easier recognition of micro-metastatic deposits in organs especially in that which do not normally express the EMA. It is found that there is immunohistological differences between sebaceous and meibomian carcinomas and this confirms that meibomian gland is a modified sebaceous gland. However, this point needs further investigations.
The localization of EMA monoclonal antibody to surface and luminal membranes of normal cells suggests that it may nave a protective function as confirmed by increasing the staining in neoplastic states which indicates that increased production, may be a response of epithelial cells to injury.
Also, the adjacent cell membrane staining is found only in malignant tumours and not in cells of normal skin and benign lesions, this may be due to poor cell contact has been reported in malignant tumours which stimulate the synthesis of antigen and this confirm the protective function of the antigen.
100 protein is a good and very useful biological indicator for malignant melanoma especially the amelanotic type and could differentiate amelanotic melanoma from sarcoma, lymphoma and undifferentiated
ma. The 5100 protein monoclonal antibody st;Tdu ng is suggested to be inversely proportional to the amount of melanin pigment. There is no relation between the 5100 protein reactivity and the cell type of the tumour (round, spindle or mixed). Unfortunately, S100 protein can not distinguish between benign and malignant melanoma. Here, there is a question which needs further study, is the melanotic
1 melanoma more mature than amelanotic type and here the melanin pigment is a marker for maturation while the Sloo protein is a marker for their neural crest origin and their rapid proliferation?
The origin of epidermal and epidermal appendageal
J tumours is still unsettled, so, in the present study
J it was attempted to throw light on this question.
•rhsns. cells, benign and malignant melanoma reacted with 5100 protein, so that they are of neural crest origin and migrate to their final locations during embryogenesis.
In eccrine spiradenoma, syringocarcinoma, and 2 cases of sweat gland carcinoma, there are a positive cells for S100 protein as that found in normal eccrine coil. So that these tumours may arise from eccrine coil and not from eccrine duct.
Basal cell carcinoma arises from the basal cell layer before its differentiation into mature keratinocytes, while squamous cell carcinoma arises from keratinocytes after maturation (i.e. after moving suprabasally). So, squamous cell carcinoma is a more differentiated tumour of the epidermis than basal cell carcinoma.
Adenoid cystic carcinoma of the face may arise from sweat glands and not from the minor salivary glands in the maxilla as it was suggested previously. This point needs further study.
ed tumour: of the scalp, is found to be formed of 2 different compartments, one from epithelial tissue and the other from connective tissue. Therefore, this tumour is a mixed one, or there is tumour meta-plasia in its stroma (fibroblasts to chondroblasts).
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Basal cell carcinoma can be differentiated from squamous cell carcinoma. The squamous cell carcinoma reacted positively with broad spectrum keratin, EMA and CEA antibodies, while the basal cell carcinoma does not react immunologically with these antibodies.
It is found also that monoclonal antibodies have a good role in diagnostic dermatopathology espec-ially in undifferentiated carcinoma. Panels of anti-
bodies should always be used where possible. The
cr of panel depends on the diagnostic
problems produced. Idealy, it should contain at least one marker of each of all tumour types entering into the differential diagnosis. So that, spurious results can be identified.
It is found that, there are changes in antigenic expression and immunoreaction with antibodies in the covering epidermis above the epidermal and epidermal appendageal tumours than that of normal epidermis. These changes may be indicative of a premalignant state in these cells and monoclonal antibodies are thus potentially useful reagents for early detection of skin malignancy.
it clonal antibodies provides us exciting insight into cellular biology, differen-tiation, evaluation and neoplastic transformation of epithelial cells. Further studies are indicated to elucidate the practical diagnostic basic research
application of poly and monoclonal antibodies. These
antibodies are becoming an important tool for the
1 biologist and diagnostic pathologist alike and promises
to provide a new and significant dimensions to the 1 molecular characterisation of the skin.