Background: Urinary Bladder Carcinoma (UBC) is a worldwide health problem ranking as the ninth most common cancer globally and the second most common malignancy in Egypt. The effectiveness of PD-1/PDL-1 immune checkpoint inhibitors in metastatic disease has stimulated its evaluation as a treatment option in HR-NMIBC and MIBC patients. Aim of the study: Studying the immunohistochemical expression of PDL-1 in UBC cases in order to evaluate its expression pattern and examine its association with various clinicopathological features and studying the possible change in the PDL-1 expression between the primary UBC and their corresponding Lymph node metastasis.
Method: The study included 50 formalin-fixed, paraffin-embedded tissue specimens of UBC. Tissue sections have been subjected to H&E staining and immunostaining study for PDL-1 expression.
Results: PDL-1 expression was detected as positive membranous immunostaining ranging between -ve/ low and high expression. Thirty-four cases (68%) showed high expression while 16 (32%) showed -ve/ low expression. Significant association was found between PDL-1 expression and tumour type, tumor grade, stage, muscle invasion and LN status (p=0.012, 0.005, 0.005, 0.045 and ˂0.001 respectively). Significant positive associations was found between PDL-1 expression and LN spread (p. <0.001). Only 12 cases had lymph node metastasis,  (4/12) (33.3%) had –ve/ low PDL-1 expression while the remaining eight cases (66.7%) had high PDL-1 expression.
Conclusion: PDL-1 expression showed a positive significant correlation with tumour type, grade and stage, muscle invasion and lymph node metastasis. Illness may be accompanied with general improvement of RV systolic and diastolic dysfunction