2022 World Conference on Lung Cancer (ePosters)-EP16.01-011. PD-L1 Expression on Cytological Imprints and Circulating Tumor Cells versus Standardized Immunohistochemistry in NSCLC

EP16.01-011. PD-L1 Expression on Cytological Imprints and Circulating Tumor Cells versus Standardized Immunohistochemistry in NSCLC

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A study compared the expression of PD-L1, a biomarker used to predict response to immunotherapy, in cytological smears and circulating tumor cells (CTCs) with the standardized immunohistochemistry staining of tumor tissue in patients with non-small cell lung cancer (NSCLC). The study aimed to determine the reliability of assessing PD-L1 expression in cytology smears or liquid biopsies when tissue is not available. <br /><br />Liquid biopsies and cytological smears were obtained from patients with suspected lung cancer. PD-L1 expression was evaluated using a PD-L1 antibody in both cytological smears and histological samples. CTCs were enriched using a microfluidic approach and PD-L1 expression was assessed on these cells. PD-L1 status was expressed as a percentage of positive tumor cells. <br /><br />Results showed that PD-L1 expression in cytology smears had a good predictive capacity for PD-L1 positivity and high PD-L1 expression. The detection rate of CTCs was comparable among different patient groups, but tend to be elevated in patients with stage IVB. PD-L1 expression was detected in the majority of liquid biopsies. Adding CTCs PD-L1 expression improved the predictive capacity of cytology smears for PD-L1 positivity and high PD-L1 expression.<br /><br />Overall, the study concluded that the assessment of PD-L1 expression in cytological smears and liquid biopsies has good agreement rates with the standardized immunohistochemistry staining of tumor tissue in patients with NSCLC. This suggests that cytology smears and liquid biopsies could be reliable alternatives for PD-L1 assessment in cases where tissue samples are not available.

Asset Subtitle

Martin Reck

Meta Tag

Speaker Martin Reck

Topic Tumour Biology and Biomarkers - Immune Biology & Immunotherapy

Keywords

PD-L1 expression

cytological smears

circulating tumor cells

immunohistochemistry staining

non-small cell lung cancer

liquid biopsies

microfluidic approach

CTCs PD-L1 expression

predictive capacity

NSCLC