Original article / research
Immunoreactivity of p53 in Urothelial Carcinomas of the Urinary Bladder
Dr. Asha Mahadevappa,
#1036, 5th Main 10th Cross,1st Stage, Vijaya
Nagar, Mysuru-570017, Mysuru, Karnataka, India.
Introduction: Urothelial Carcinomas (UC) are heterogenous disease with unpredictable outcome. Risk stratification plays an important role in the management as 70% tumours are Non-Muscle Invasive (NMI) at the time of diagnosis. It is difficult to make prognosis for individual patients due to high rates of recurrence and progression. Over-expression of p53 cell cycle regulator protein is associated with high grade, high stage of bladder cancer and important in the multistep progression with an unfavourable prognosis. The p53 immunohistochemical staining intensity and score status identifies patients needing early cystectomy for treatment of NMI or aggressive adjuvant therapy after cystectomy.
Aim: To assess the immunohistochemical expression patterns of p53 in UC of the urinary bladder and to find out the relationship between p53 over expression with clinicopathological parameters like grading and pathological staging.
Materials and Methods: The study was conducted in JSS Medical College and Hospital, JSS Academy of Higher Education & Research, Mysuru. A total of 50 cases of UC of the bladder were included in the study (2 years each of retrospective-October 2012 to September 2014 and prospective study-October 2014 to September 2016) over a duration of two years. The over expression of p53 antigen was evaluated by Immunohistochemistry (IHC) as intensity and a score based on the percentage of tumour cells staining positive after counting at least 500 cells in each case using high power objective of the microscope (x400).
Results: Among 50 cases, 39 (78%) tumours were high grade and 11 were low grade. A 49 (98%) were positive for p53 over expression and 01 (2%) high grade non papillary tumour was negative. Higher intensity (3+) and score (4+) of p53 over expression was seen with higher grade than lower grade with statistically significant p-value (intensity - < 0.001, score - 0.006). Also, when evaluated separately this correlation was found significant in high grade NMI (p-value: intensity- 0.021, score – 0.025) rather than muscle invasive tumours. No relationship was established between p53 over expression with pathological stage of tumour and other clinicopathological parameters.
Conclusion: Higher p53 over expression is associated with higher grade, particularly in NMI tumours which may go for progression and recurrence. Therefore, p53 over expression by IHC can provide important prognostic information in risk stratification of UC of the bladder. It aid in appropriate modification of treatment management and better understanding biological behaviour of UC.
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