الفهرس 
AmeloblastomaOnly 14 pages are availabe for public view
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Abstract
Ameloblastoma and KCOT Ameloblastoma (AM) are most
commonly encountered in the jaw bones. The etiopathogenesis is
idiopathic. Ameloblastoma (AM) is a very common odontogenic tumor in
the oral cavity whose idiopathic nature manipulates scholars and
clinicians. The etiopathogenesis of AM is controversial. The involved
cellular changes - including proliferation, differentiation, senescence,
tumorigenesis, etc - which are identified through the
immunohistochemical workup contribute significantly to our
contemporary nosology of this aggressive benign tumor.
Keratocystic odontogenic tumor (KCOT) is controversially
considered a cyst and a tumor. According to WHO, KCOT is a benign,
unicystic or multicystic, intraosseous tumor of odontogenic origin. Either
syndromic or non-syndromic, the PTCH gene is proven participant in the
etiology.
This study contrasted the expression of CD44 in AM and KCOT.
CD44, a transmembrane glycoprotein, is a homing cell adhesion molecule
and is a stem cell marker for breast, prostate, pancreatic cancers and for
several head and neck benign and malignant tumors. Receptor Activator
of NF-κB (RANK), or CD 256, is a homotrimeric transmembrane protein
member of the TNF receptor superfamily. It is normally expressed in
mature osteoclasts and in dendritic cells. Oncologically, RANK is known
to be expressed in some cancer cells, including breast and prostate
cancers. RANKL is produced mainly by the osteoblastic lineage and
immune cells, and is able to link to RANK, stimulating bone resorption
through osteoclastogenesis and multinucleated mature osteoclasts
activation.Forty formalin-fixed, paraffin-embedded specimens were included
in this study, twenty cases diagnosed as Ameloblastoma and twenty cases
diagnosed as KCOT.
Histopathological examination, using haematoxylin and eosin was
used to confirm the diagnosis. Using peroxidase-antiperoxidase method
for immunohistochemical examination, each lesion was stained with
antibodies against CD44 and RANK. Analysis and interpretation of the
results was performed using the image analysis software (Image J1.43r) to
measure the surface areas of immunopositivity for CD44 and RANK.
For all cases, the area fraction of CD44 and RANK
immunopositivity for at least four different microscopic fields was
measured. Then the mean area fraction of immunopositive cells for each
case was calculated and used for statistical analysis. Statistical analysis
was performed using student‟s t-test to compare between RCs and
KCOTs. Pearson‟s correlation coefficient was used to determine any
significant correlation between CD44 and RANK.
The immunohistochemical results of the present study
demonstrated that.There is a highly significant difference between the
immunoexpression of CD44 in AM and OKCT. and also in immune
expression of RANK in AM and OKCT. So The results show that KCOT
demonstrates a stronger positivity than AM.
In conclusion, the breakdown in the cellular adhesion, as a clue to
osteoclastogenesis, is stronger in KCOT than in AM. The strong
expression of KCOT for the monoclonal antibody of CD44 was against
the cystic nature and supports the neoplaticity of KCOT. CD 44 and
RANK may play a significant prognostic role in predicting the recurrence
of AM and KCOT and may have a synergistic osteoclastic interaction.