非小细胞肺癌中程序性死亡配体 1 表达与 CD8 阳性 TIL（肿瘤浸润淋巴细胞）密度及其与组织病理学分级的相关性

Non-small cell lung carcinoma (NSCLC), comprising 85% of lung cancers, remains a leading cause of cancer mortality despite advances in treatment. Immunotherapy, particularly immune checkpoint inhibitors targeting the PD-1/PD-L1 axis, has revolutionized therapy, though outcomes vary.

This study aimed to explore the association between PD-L1 expression, CD8 tumor-infiltrating lymphocyte (TIL) density, and histopathological grading in NSCLC.

Our retrospective, single-center cohort comprised 64 biopsy samples of NSCLC. PD-L1 and CD8 TIL density were assessed through immunohistochemistry.

We also classified the tumors into four groups based on the PD-L1 and CD8-positive TIL statuses and evaluated their association with clinicopathological parameters. Male subjects were the predominant population in the study group (86%), with a mean age of 60 years. Most of the cases were smokers/ex-smokers (70. 3%). Among 64 cases, PD-L1 positivity was observed in 62. 5%, correlating with poorly differentiated tumors (grade 3) (p=0.

03), suggesting its association with poor prognosis. Among PD-L1-positive cases, 55% had high expression and 45% had low expression. CD8 TIL density was low in 62. 5% of cases and showed no significant correlation with clinical variables. Combined analysis revealed that 42. 19% of cases were PD-L1+/CD8 low, a phenotype indicative of immune evasion and aggressive tumor behavior.

Overall, our results emphasize that while PD-L1 immunohistochemistry remains a critical tool for identifying candidates for immunotherapy, it is not a standalone predictor of treatment response. Integrating CD8 TIL density provides additional prognostic information, potentially guiding more personalized treatment strategies.