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COEXPRESSION
OF P53 AND KI-67 MARKERS IN ADENOMAS OF THE COLON
Stojiljkoviĉ
B, Goluboviĉ A, Baltiĉ V, Mihajloviĉ O, Petroviĉ T, Breberina
M.
Institute
of Oncology Sremska Kamenica, Sremska Kamenica, Serbia
and Montenegro
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ABSTRACT
The
specimens of adenomas of colonic mucosa obtained after total colectomy
performed due to surgical treatment of the carcinomas were immunihistochemically
analyzed with p53 and Ki 67 markers in order to prove their neoplastic
and proliferative potential by means of coexpression visualization.
Genetic alteration expressed as p53 mutation of tumor suppressor
gene, which is present in most human carcinomas, may be proved by
immunohistochemical detection of abnormal nuclear protein accumulated
in cell. On the other side Ki-67 is an antigen, which corresponds
to nuclear nonhistone protein exprimated in cell in G1, G2, M and
S phase, and can also be histochemically verified. Coexpression
of these two markers speaks in favor of proliferative potential
of examined cell. We analyzed 10 adenomas of the colon obtained
after colectomy due to adenocarcinomas, and 10 polypoid adenomas
with epithelial dysplasia of various degrees diagnosed on the specimens
obtained after endoscopy. All tissue samples were first fixated
in neutral, buffer formalin and embedded in paraffin blocks, which
were used to make routine HE slides and slides for immunohistochemical
analysis using p53 and Ki-67 markers. All histological specimens
were examined by light microscope Leica DMLB. As expected, positive
immunohistochemical reaction of various distribution and intensity
for both markers was evident in all analyzed specimens of adenomas
obtained after colectomy performed due to diagnosed colon cancer.
However, in the group of endoscopically verified adenomas with various
epithelial dysplasia two cases of positive reaction, i.e. coexpression,
were observed. Coexpression visualization of p53 and ki-67 markers
is considered to be a predictor of neoplastic proliferation and
progression of histologically yet benign lesions of colonic mucosa,
thus suggesting the use of radical surgery. At the same time, their
negative reaction suggests the reversibility of observed dysplastic
lesions, no matter how much they are expressed, because often they
are the consequence of inflammation that seeks for conservative
treatment. |
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Keywords:
Colorectal carcinoma, Neoplastic proliferation, p53, Ki-67,
Immunohistochemical analysis |
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