Aim: The aim of the study was to determine the association
of p53 expression with grade, stage, LVI status, histopathological subtype and
topography of CRC.
Introduction: The topography of colon tumours is also
different with right-sided colon tumours more commonly observed in developed
high-income countries whilst many Sub-Saharan African countries report a high
proportion of left-sided colon tumours, especially rectal tumours. In Uganda,
the Kampala Cancer Registry has reported a steady increase in colorectal cancer
(CRC) in the past 20 years, however, is still lower compared to developed
high-income countries. Colon tumour topography varies as well; in
industrialized high-income countries, right-sided colon tumours are more
frequently detected than in developing low-income ones. In colorectal cancer
(CRC), the p53 gene is often altered. This leads to the production of an
aberrant protein, which can be detected early by immunohistochemistry. A poor
prognosis and reduced survival have been associated with the detection of p53
in malignant cells.
Methods: During the period 2008 to 2021,
immunohistochemistry was carried out on 51 patients’ paraffin-embedded tissue
blocks of CRC. TP53 expression was detected using the indirect immunoperoxidase
method which uses monoclonal antibody p53, DAKO Agilent USA, Clone DO-7. The
grade and histopathological subtypes of CRC were evaluated using the
haematoxylin and eosin stain. The demographic data and topography of the
tumours were obtained from the clinical patients’ files and the Kampala Cancer
Registry.
Results: Out of 51 patient tissue blocks that were studied,
27(52.9%) expressed p53 in the nucleus of malignant CRC cells. There were
20(74.1%) left-sided colon tumours and 7(25.9%) right-sided colon tumours that
expressed p53 and this reached statistical significance (p=0.0004). The
presence of p53 expression was also significantly associated with the presence
of lymphovascular invasion (p=0.0561) and the classical adenocarcinoma
histological subtype (p=0.0000). There was a negative correlation between CRC
grade and p53 expression (r=-0.1189; p=0.4059) and between CRC stage and p53
expression (r=-0.1702; p=0.2324). The present study did not evaluate the role
of radiotherapy in the response to rectal tumours that have positive p53
expression, however, future studies may evaluate this role in Ugandan patients.
Similar to other parts of the world in Ugandan patients, p53 expression is more
commonly present in left-sided colon tumours.
Conclusions: The intensity of p53 expression is not
influenced by stage and grade of CRC. Similar to other parts of the world, p53
expression is more commonly present in left-sided tumours. Therefore these
findings support the theory, that right-sided colon tumours have a different
pathogenesis than left-sided colon tumours, and hence have a different
prognosis. Further studies should be carried out to determine the types of
genetic mutations or epigenetic factors responsible for the difference in
prognosis between left-sided and right-sided CRC in Ugandan patients.
Author(s) Details
Richard Wismayer
Department of Surgery, Masaka Regional Referral Hospital,
Masaka, Uganda, Department of Surgery, Faculty of Health Sciences, Equator
University for Science and Technology, Masaka, Uganda, Department of Surgery,
Faculty of Health Sciences, Habib Medical School, IUIU University, Kampala,
Uganda and Department of Pathology, School of Biomedical Sciences, College of
Health Sciences, Makerere University, Kampala, Uganda.
Julius Kiwanuka
Department of Epidemiology and Biostatistics, School of
Public Health, College of Health Sciences, Makerere University, Kampala,
Uganda.
Henry Wabinga
Department of Pathology, School of Biomedical Sciences,
College of Health Sciences, Makerere University, Kampala, Uganda.
Michael Odida
Department of Pathology, School of Biomedical Sciences,
College of Health Sciences, Makerere University, Kampala, Uganda and Department
of Pathology, Faculty of Medicine, Gulu University, Gulu, Uganda.
Please see the link:- https://doi.org/10.9734/bpi/mria/v10/1176
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