الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Head and neck cancer among the most common incident cancers in men worldwide. Early detection is the key to higher survival rate against this type of cancer. Cytokeratins are essential intracellular components, reflecting distinct cellular properties and differentiation stages in epithelial tissues. The CYFRA 21-1 assay, which is the soluble fragment of cytokeratin 19, has been proven capable of early detection of epithelial carcinomas .
This study was conducted to correlate the immunoexpression of CK 19 with the concentration of its salivary fragments (CYFRA 21-1) for early detection of induced dysplastic changes prior to malignant transformation in experimental rat .
The study was conducted on fourty four male albino rats with age ranging from 3 to 4 months and with a mean weight of 220 gm. They were divided into two groups, each consisting of 22 rats, the first group represents the control group I and the second group represents induced group II. Each group was subdivided into 5 subgroups A, B, C, D and E according to the time of euthanization with intervals of 9,12,15,18 and 21 weeks from time of induction respectively. In induced group II, the tongue mucosae of each rat were painted (topically) with dimethylbenz-anthracene and formaldehyde, whereas group I served as positive control .
The Rats were euthanized according to the Research Animal Guidelines of Euthanasia (2013). The dissected tongue mucosae of rats were processed routinely to obtain 5 microns thick sections. These sections were examined histologically by H&E stain and immunohistochemically by CK 19 antibody. Moreover Saliva samples were collected from all the groups to evaluate the level of CYFRA 21-1 concentration by ELISA assay .
Histopathologically, at 12, 15, 18 weeks of the DMBA induction, the main changes compared to control group consisted of mild, moderate and severe dysplastic changes. At 21weeks of DMBA application the rat tongue mucosae revealed disruption of the basement membrane and invasion of dysplastic epithelial cells into the underlying connective tissue with development of well differentiated squamous cell carcinoma .