Comparison of PD-L1 detection methods, platforms and reagents in bladder cancer

In this retrospective study, we collected 282 bladder cancer patients diagnosed from 2011 to 2018. Two mechanisms, fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), were used to detect programmed death molecule ligand 1 (PD-L1) expression, and these analyses were performed on different platforms using different antibodies (22C3, 28-8, and SP263). The results were compared, and related clinical parameters were analysed to explore the consistencies and correlations between different detection methods, clonal antibodies and platforms for the detection of PD-L1 in bladder cancer patients to more effectively identify patients who are suitable for immunotherapy. The rate of PD-L1 positivity with 28-8 (42.3 %) was higher than that with 22C3 (22.1 %) or SP263 (22.1 %). The rate of PD-L1 positivity with SP263 was consistent with that of 22C3, and patients with positive PD-L1 expression detected by SP263 had longer overall survival in clinical parameter analysis. However, the rate of PD-L1 positivity with FISH was only 2.10 %, and the rate of agreement between FISH and IHC was only 1.06 %. In conclusion, the detection of PD-L1 with SP263 and IHC was more consistent and had a higher prognostic value, providing guidance for clinical diagnosis and treatment. The clinical application of FISH for PD-L1 detection needs to be further explored.