Abstract 5172: B cell content in the tumor microenvironment is associated with improved survival in stage II lung adenocarcinoma
Authors: Valiev Ivan , Kotlov Nikita , Belozerova Anna , Lopareva Aleksandra , Butusova Anna , Samarina Naira , Boiko Alexandra , Degryse Sandrine , Sequist Lecia , Mino-Kenudson Mari , Fowler Nathan , Bagaev Aleksander , Lanuti Michael , Dagogo-Jack Ibiayi 
Published: June 2022

Abstract
In non-small cell lung cancer (NSCLC), likelihood of cure is heavily influenced by stage at diagnosis. In contrast to stage I where surgery achieves cure for &gt;70% of patients, the majority of patients with stage II NSCLC will develop recurrent disease after surgery. The addition of chemotherapy is associated with modest improvement in survival. Biomarkers that help identify patients at higher risk of relapse following curative intent therapy remain elusive.
In this study, we performed comprehensive profiling of resected stage II lung adenocarcinomas (LUAD) (n=29) to identify features associated with favorable prognostic outcomes. Whole exome (WES) and bulk RNA sequencing (RNAseq) were performed on frozen lung tumor specimens and corresponding normal lung tissue. Novel algorithms were used to digitally reconstruct the tumor microenvironment (TME). H&E slides were reviewed to characterize the immune infiltrate and identify tertiary lymphoid structures (TLS). Patient outcomes were collected and matched to pathological samples. To further validate initial findings, we then created and tested a functional B-cell signature on cohorts as described below.
In the retrospective cohort, 13 (45%) patients developed recurrent disease and 10 (34%) died during the 3+ year follow-up period. Neither the overall density of immune infiltrate nor detection of TLS predicted for improved relapse-free survival (RFS) or overall survival (OS). Similarly, tumor mutational burden (assessed by WES), histological grade (assessed by RNAseq), and expression of immune checkpoints (PD-L1, PD-1, CTLA-4) were not associated with RFS or OS (log-rank test P &gt; 0.05 for both OS and RFS in all comparisons). Interestingly, higher B-cell content in the TME (stratified as high vs low based on 10% threshold value), as deconvolved using validated algorithms (and confirmed via H&E review), was associated with improved OS (log-rank test P = 0.05) with a trend towards improved RFS (P = 0.2). We conducted the same analysis using a TCGA RNAseq cohort of stage II LUAD patients (n = 76) and confirmed that high B-cell levels in the TME were significantly associated with longer OS in stage II LUAD patients (P = 0.03). Finally, to validate our findings with a larger dataset, we developed a functional B-cell gene expression signature which significantly correlated with levels of B cells in both the TCGA (Spearman’s rho = 0.83, P &lt; 0.001) and 29-patient cohort (Spearman’s rho = 0.91, P &lt; 0.001). When this signature was applied to publicly available expression array data, B-cell enrichment status was significantly associated with OS in the external meta-cohort of stage II LUAD patients (log rank test P = 0.004, n=564).
Abundant B-cell infiltrate in the TME is associated with improved survival in patients with surgically resected stage II LUAD. Quantification of B-cell content using RNAseq warrants further investigation for use in routine clinical practice.
Citation Format: Ivan Valiev, Nikita Kotlov, Anna Belozerova, Aleksandra Lopareva, Anna Butusova, Naira Samarina, Alexandra Boiko, Sandrine Degryse, Lecia Sequist, Mari Mino-Kenudson, Nathan Fowler, Aleksander Bagaev, Michael Lanuti, Ibiayi Dagogo-Jack. B cell content in the tumor microenvironment is associated with improved survival in stage II lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5172.