Analysis of PD-L1 Immunohistochemistry Results for Different Sampling Procedures of Non-small Cell Lung Carcinoma. Can We Use Cell Blocks for Evaluation of PD-L1?

Authors : Esin KAYMAZ, Haldun UMUDUM

Pages : 215-222

View : 17 | Download : 10

Publication Date : 2022-12-15

Article Type : Research Paper

Abstract :Aim: Current guidelines recommend evaluating the expression of PD-L1 immunohistochemically in most tumors, especially lung cancer. However, it is not easy to evaluate the immunohistochemical staining of PD-L1 because of the tumor heterogeneity. Therefore, we aim to evaluate the different patterns of PD-L1 in the lung’s nonsmall cell carcinoma and the relationship with clinicopathological features. We also wanted to see if cell blocks obtained from cytology materials can be an alternative for PD-L1 immunohistochemistry. Material and Method: We retrospectively analyzed the immunohistochemical patterns of PD-L1 performed between 2018 and 2019. Biopsy/aspiration procedure of tumors, tumor type, patient’s age, and gender were reviewed. Positive tumor cells insert ignore into journalissuearticles values(percentage); were categorized according to density and distribution as negative insert ignore into journalissuearticles values( 50%);. Results: Material adequacy was found to be satisfactory in evaluating PD-L1 in the cases of cell blocks. Positive staining with PDL1 was detected even with a small number of tumor cells in the cell block. For optimal evaluation of PD-L1 expression in the cell block, the tumor cell ratio of 10% is significant insert ignore into journalissuearticles values(p=0.002);. The cases with negative PD-L1 expression mostly belonged to small biopsy samples insert ignore into journalissuearticles values(48.3%);. However, the difference in PD-L1 expression in histological and cytological samples was insignificant insert ignore into journalissuearticles values(p=0.79);. Besides this, expression of PD-L1 was negative in almost half of the cases insert ignore into journalissuearticles values(48.3%); diagnosed with squamous cell carcinoma. In adenocarcinoma cases, the PD-L1 expression rate was between 1–49 % in more than half insert ignore into journalissuearticles values(51.8%); of them. The difference in histological subtype was not significant in PD-L1 staining insert ignore into journalissuearticles values(p=0.009);. Conclusion: In conclusion, we can use cell blocks for immunohistochemical evaluation of PD-L1 expression. Analysis of PD-L1 staining in cytological and histological tissue samples may be a guide for other studies.
Keywords : PD L1, tumor, lung carcinoma, cell block