Background: Immune checkpoint inhibitors targeting either programmed cell death protein 1 (PD-1) or programmed cell death ligand 1 (PD-L1) have been established as a novel target for immunotherapy in non-small cell lung cancer (NSCLC). Prevalence of PD-L1 expression in NSCLC varies from 13% to 70%, with sparse data from the Indian subcontinent. In this study, we looked at PD-L1 expression and its association with demographic, clinical, radiologic and pathologic parameters in NSCLC patients.
Methods: This was an observational study carried over a period of 18 months in which 65 patients of NSCLC were included. Immunohistochemistry (IHC) for PD-L1 was done using an automated IHC stainer and testing was performed using PD-L1 IHC CAL10. For statistical analysis, unpaired t test, Chi square test, Fisher's exact test and binomial logistic regression were used. P < 0.05 was taken to be statistically significant.
Results: Mean age of the patients was 62.9 ± 9.2 years, and majority (87.3%) of them were males. Seventeen (26.2%) patients expressed PD-L1, among whom 10 had high PD-L1 expression (≥50%) and 7 had low PD-L1 expression (1-49%). PD-L1 expression was seen in 13 out of 43 cases of squamous cell carcinoma (SCC) and 4 out of 15 cases of adenocarcinoma. On applying binomial logistic regression analysis, association between smoking and PD-L1 expression was found to be insignificant.
Conclusion: Almost a quarter of NSCLC cases were PD-L1 positive without any difference in expression between SCC and adenocarcinoma. PD-L1 status was not associated with any specific demographic, clinical or radiologic parameter including the histologic subtype.
Keywords: Clinical; Histologic; Immunotherapy; Lung cancer; Programmed cell death ligand 1.
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