Digital quantitative immunofluorescent detection of p53 protein in urinary bladder cancer tissue samples

Bladder cancer is a significant health problem and is the fourth most common malignancy in the Western world. Histologically, transitional cell carcinoma (TCC) is the most common subtype and represents nearly 90% of all bladder cancers. Mutations of the tumour suppressor gene p53 are the most frequent genetic alteration found in human cancers, including urinary bladder carcinoma. Numerous studies have attempted to define p53 as a molecular marker with clinicopathological and predictive values. In this study we have investigated tissue samples of histopathologically confirmed TCC of the urinary bladder from 70 patients. Normal urinary bladder mucosa obtained from 40 patients with nonmalignant diseases were used as a negative control group. Immunofluorescence detection was performed using double-sandwich antibody technique, the microscope images were captured by digital camera and analyzed by ImageJ software. Corrected fluorescent intensity values corresponding to average malignant cells' nuclear p53 staining were calculated from each patient sample. We found that the mean corrected fluorescence intensity values of TCC samples grade I and II did not differ statistically significantly. On the contrary, those values were significant between the TCC grades II and III, as well as between grade I and III. In addition, a high correlation of p53 fluorescence intensity values from superficial TCC samples with the invasive TCC samples was found. However, the data showed no predictive value of p53 nuclear accumulation in TCC samples in terms of recidive, metastasis or cancer-related death, at least within the 2-years follow-up period. Given the relatively small size and heterogeneity of our patient groups, however, further studies are needed to demonstrate the clinicopathological value of digital quantitative immunofluorescent detection of nuclear p53 in TCC samples.