Fading With Time of PD-L1 Immunoreactivity in Non–Small Cells Lung Cancer Tissues: A Methodological Study

In this study we selected 58 consecutive NSCLC surgical specimens that underwent pathologic examination from January 2014 to July 2015. Using a tissue microarray approach we evaluated the IHC expression of PD-L1 in tumor-infiltrating lymphocytes and tumor cells (TCs) and compared the ICH staining with tumor histology, grade and the age of the tissue blocks. The main new finding was the fading of PD-L1 IHC expression in TCs in tissues processed in 2014 compared with 2015. PD-L1 expression in tumor-infiltrating lymphocytes in the 2 years was similar. We also found a significant higher immunoreactivity of TCs in high grade NSCLC and in the squamous carcinoma histotype compared with low grade tumors and the adenocarcinoma histology (P=0.013). We demonstrated that the IHC evaluation of PD-L1 in NSCLC archival tissues is feasible and can be implemented in a routine pathology setting, but it should be carefully assessed in tissue blocks older than 1 year.
Source: Applied Immunohistochemistry and Molecular Morphology - Category: Chemistry Tags: Research Articles Source Type: research