Unraveling the Nexus: Tumor Mutational Burden, PD-L1 Expression, and Oncogenic Alterations in Non-Small Cell Lung Cancer Cytology Specimens

Authors

Min Dai
Francis Anthony San Lucas
Hector Alvarez
Leomar Ballester
Hui Chen
Keyur P Patel
Asif Rashid
Shun Rao
Mark J Routbort
Gloria Sura
Keith Sweeney
Gokce Toruner
Peng Wei
Richard Yang
Hyvan Dang
Rajyalakshmi Luthra
Sinchita Roy-Chowdhuri

Language

English

Publication Date

4-1-2026

Journal

Cancer Cytopathology

DOI

10.1002/cncy.70090

PMID

41891376

PMCID

PMC13022943

PubMedCentral® Posted Date

3-27-2026

PubMedCentral® Full Text Version

Post-print

Abstract

Background: PD-L1 expression and tumor mutational burden (TMB) are biomarkers for immune checkpoint inhibitor (ICI) therapy in non-small cell lung cancer (NSCLC); however, patients harboring oncogenic alterations have limited benefit from ICIs. The impact of oncogenic alterations on TMB and PD-L1 tumor proportion score in lung cytology specimens is poorly understood. Herein, the association between oncogenic alterations, TMB, and PD-L1 in NSCLC cytology specimens is explored.

Methods: Next-generation sequencing results from 312 NSCLC cytology specimens were retrospectively reviewed that interrogate 610 genes and select immuno-oncology signatures. TMB and PD-L1 immunohistochemical expression across oncogenic alterations were analyzed to explore associations.

Results: Of the 312 cases evaluated, 192 harbored NSCLC-specific oncogenic alterations. Relative to EGFR-mutated tumors, TMB was significantly higher in KRAS (padj = 2.7 × 10-4), ERBB2 (padj = .023), and BRAF (padj = .023) -mutated tumors but lower in ALK-rearranged tumors (padj = .005). Significantly higher PD-L1 expression was seen in tumors with KRAS (padj = .002) and MET exon 14 (padj = 1.06 × 10-4) when compared to EGFR-mutated tumors. Strong positive correlations between TMB and PD-L1 were observed in ERBB2-, KRAS-, and BRAF-mutated tumors when evaluated as continuous variables. TP53 mutations further enhanced immunogenicity when co-occurring with KRAS, ERBB2, or BRAF mutations but this effect was not observed in EGFR-mutated tumors.

Conclusions: These findings demonstrate distinct TMB and PD-L1 profiles that may identify patients who will benefit from ICI therapy. Cytology specimens provide adequate material for biomarker testing, which underscores their value in guiding immunotherapy decisions.

Keywords

Humans, B7-H1 Antigen, Carcinoma, Non-Small-Cell Lung, Lung Neoplasms, Male, Biomarkers, Tumor, Female, Mutation, Retrospective Studies, Middle Aged, Aged, High-Throughput Nucleotide Sequencing, Adult, Cytodiagnosis, Aged, 80 and over, Immune Checkpoint Inhibitors, cytology, immuno‐oncology, next‐generation sequencing, non–small cell lung cancer (NSCLC), PD‐L1, tumor mutational burden (TMB)

Published Open-Access

yes

Recommended Citation

Dai, Min; San Lucas, Francis Anthony; Alvarez, Hector; et al., "Unraveling the Nexus: Tumor Mutational Burden, PD-L1 Expression, and Oncogenic Alterations in Non-Small Cell Lung Cancer Cytology Specimens" (2026). Faculty, Staff and Student Publications. 6777.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/6777