الفهرس 
Immunohistochemical Technique (IHC)
Antigen RetrievalOnly 14 pages are availabe for public view
 |  | from | 142 |  |  |
| | | from | 142 | | |
Abstract
Osteosarcoma of the jaws is an aggressive, malignant mesenchymal
tumor, which is characterized by the formation of osteoid tissue. There are
multiple factors that have an influence on the prognosis of OS, The wellknown prognostic factors are age, tumor site, tumor size and histological
type.
Reversion-Inducing-Cysteine-Rich Protein With Kazal Motifs, a novel
MMP inhibitor is widely expressed in various normal human tissues but
is downregulated in tumor cell lines and oncogenically transformed cells.
RECK gene encodes a membrane-anchored glycoprotein that suppresses
tumor invasion and angiogenesis by regulating MMP-2, MMP-9 and
MT1-MMP by unknown mechanism. This suggests that RECK may be
involved during tumor progression, invasion and metastasis.
Osteopontin is a secreted and calcium binding phosphorylated
glycoprotein and expressed constitutively in a limited number of normal
tissues, stress-responsive physiological conditions, and abnormally
elevated in some pathological conditions. OPN is considered as cytokine
that regulates cell pathways in the immune system. OPN was also
expressed in various malignancies and may play important role in
tumorigenesis, tumor invasion, and metastasis in various malignancies. In
addition, OPN expression was associated with poor prognosis. OPN was
also suggested to be a clinically useful marker for predicting biochemical
recurrence for many tumors. This study was conducted in order to evaluate RECK gene expression
level by RT-PCR and OPN immunoexpression in relation to patient
clinical parameters and histological subtypes of conventional JOS, as
well as to investigate the possible relationship that might exist between
each marker individually with clinical parameters and histological
subtypes and then between both of them with clinical parameters and
histological subtypes. RECK gene and OPN were selected because it was
thought that they might have diagnostic as well as prognostic values.
Twenty-eight cases of conventional JOS were selected and classified
according to their histopathological features into eleven chondroblastic,
nine osteoblastic and eight fibroblastic subtypes. For RT-PCR assay,
quantitative assessment of RECK gene level was performed using SYBR
Green qPCR master mix. Real-time PCR amplification and analysis were
performed using an Applied Bio system with software version 3.1. The
collected data was tabulated and used for statistical analysis. While
immunohistochemical staining using the biotin-streptavidin
immunoperoxidase technique was performed with OPN. The
immunostained slides were examined by light microscopy and
photographed. The photographs were then analyzed using image analysis
software. For all cases, the mean count of immunopositivity for four
different microscopic fields was measured. The mean count for each case
was then calculated and used for statistical analysis.
Real Time-PCR results of the present study showed that the highest
expression of RECK gene was noted for the chondroblastic cases
followed by osteoblastic and fibroblastic cases. While
immunohistochemical results revealed that the highest mean count ofOPN was noted for the fibroblastic cases followed by the osteoblastic and
chondroblastic cases respectively.
ANOVA test revealed statistically significant difference of RECK gene
and OPN expression between different histological subtypes of JOS
when compared with normal bone (p = 0.000).
Student t-test revealed a significant difference of RECK gene expression
in patient gender only (p = 0.006). While t-test revealed statistically
significant difference of OPN expression in age groups as well as in
tumor grades.
In addition, statistical results of Pearson’s correlation analysis showed
that there was non-significant weak inverse correlation between RECK
gene and OPN expression in different clinical parameters of JOS (r = -
0.170) (p = 0.384). While revealed a significant inverse correlation
between them in different histological subtypes of JOS (r = -0.578) (P =
0.000).
Based upon these data it could be concluded that expression of RECK
gene and OPN in JOS might indicate their usefulness as prognostic
marker in predicting the outcome of patients. In addition, according to
the difference in their expression between different histological subtypes
of JOS; RECK and OPN could be used as a useful indicator that could
help to stratify JOS subtypes.