Diverse pattern of inflammatory cells infiltration in the microenvironment of non-small cell lung cancers (NSCLCs) has key implication for successful immunotherapeutic approaches (Gajewski et al. Nat Immunol 2013). However, study of these cells remains challenging particularly in advanced disease where tumor resection is never possible. We hypothesized that transcriptomic study of bronchoalveolar lavage (BAL) cells is useful in this setting to identify characteristic gene expression of immunological significance.
BAL cells were obtained from 13 patients of advanced NSCLC and 6 normal controls. In NSCLC group, lavage was performed from the lung segment where tumor was located. RNA was extracted and hybridized to Affymetrix HG-U133 plus2 transcriptomic microarray. Raw intensity data was normalized by Robust Multi-Array Average and analyzed for differential expressed genes (DEGs) using Bioconductor R limma package.
A total 129 DEGs were identified whose gene ontology enrichment analysis revealed the top over-represented pathways as circulating immune complex (GO: 0042571, p=2.2x10−10), FCGR activation (REAC: 2029481, p=5.4x10−11), and regulation of B cell activation (GO: 0050864, p=2.4x10−5), in which a number of up-regulated genes encoding immunoglobulins, Src family kinases and interleukin (IL)-10 were noted. We integrated the immunoglobulin genes into a signature and calculated the enrichment score for each subject using Gene Set Variation Analysis (Sonja et al. BMC Bioinformatics 2013). Medium to high correlation of immunoglobulin signature with IL-10 (Pearson’s r: 0.64, p=0.003), with FCGR2B (Pearson’s r: 0.43, p=0.066) and FCGR2B with IL-10 (Pearson’s r: 0.50, p=0.029) were determined. In addition, mild to medium correlation were identified between IL-10 and Src family kinases BLK (Pearson’s r: 0.48, p=0.038), LCK (Pearson’s r: 0.40, p=0.090) and YES1 (Pearson’s r: 0.25, p=0.300).
Transcriptome of BAL cells around advanced NSCLCs showed characteristic expression of immunoglobulin signature that may implicate the immunosuppressive property in tumor milieu.
Clinical trial identification
Legal entity responsible for the study
Chih-Hsi Scott Kuo MD
Chang Gung Medical Foundation
All authors have declared no conflicts of interest.