Single-Cell Immune Profiling Reveals Lung Cancer Changes
Single-cell RNA sequencing and flow cytometry of tissue and blood samples from lung cancer screening cohorts reveal distinct immune cell dynamics during the progression of preinvasive bronchial lesions into invasive non-small-cell lung cancer (NSCLC).
The research builds on findings from longitudinal surveillance and prospective clinical trials, including the UCLH bronchoscopy study, SUMMIT, ASCENT, and ALPINE cohorts. These initiatives track high-risk individuals, such as heavy smokers undergoing low-dose computed tomography (LDCT) screening and bronchoscopy evaluations.
UCLH Study Monitors Bronchial Lesions for Cancer Progression
The UCLH bronchoscopy surveillance study monitors patients with preinvasive bronchial lesions to track molecular and histological changes linked to cancer progression. Low-grade lesions are monitored annually, while high-grade lesions (HGLs)—such as severe dysplasia and carcinoma in situ—are monitored every three to six months. Patients unable to provide informed consent or those diagnosed with invasive carcinoma at recruitment were excluded from this specific surveillance arm.
Prospective cohorts like SUMMIT and ASCENT evaluate the implementation of LDCT screening in diverse populations across London and validate multicancer early detection blood tests. Eligible participants aged 55 to 77 years provided blood samples during pre-diagnosis surveillance. Additional tissue samples were gathered during surgical resection for screen-detected lung cancer.
The ALPINE study functions as a continuation of these screening efforts, supplying blood and peripheral blood mononuclear cell (PBMC) samples from patients undergoing targeted lung health checks.
Researchers Use Single-Cell Sequencing to Process Tissue Biopsies
Tissue biopsy samples of preinvasive lesions collected during autofluorescence bronchoscopy (AFB) underwent enzymatic digestion using collagenase and DNase I at 37 degrees Celsius. Resulting single-cell suspensions were filtered through 70-micrometre strainers and treated with red blood cell lysis buffer before 10x Genomics single-cell sequencing preparation.
Peripheral blood mononuclear cells were isolated using Ficoll Paque Plus density gradient centrifugation. Researchers performed fluorescence-activated cell sorting (FACS) to isolate specific T-cell populations, including regulatory T cells and non-naive T cells, utilizing antibodies directed against markers such as CD3, CD4, CD25, CD45RA, and CCR7. These sorted populations were prepared using single-cell kits with VDJ T-cell receptor sequencing amplification.
What Remains Unknown in Lung Cancer Progression
While single-cell profiling maps the presence of specific immune cell populations across lesion grades, the exact molecular triggers driving the transition from high-grade preinvasive lesions to invasive carcinoma remain undetermined. Clinical investigators have not yet fully established how systemic peripheral blood markers reliably predict local tissue invasion in individual patients prior to surgical biopsy confirmation.
The specific impact of diverse smoking histories and concurrent chronic inflammatory conditions on the localized T-cell receptor repertoire requires further longitudinal observation. Research teams continue to analyze follow-up data from ongoing prospective cohorts to clarify these cellular mechanisms.
Frequently Asked Questions About Lung Cancer Screening Studies
Which patient cohorts provided samples for the analysis?
Samples were gathered from the UCLH bronchoscopy surveillance study, the SUMMIT and ASCENT prospective screening cohorts, the ALPINE biomarker study, and the Molecular Pathogenesis of Lung Disease II investigation.
What specific cell types were isolated for single-cell sequencing?
Researchers isolated single-cell suspensions from bronchial mucosal biopsies as well as sorted peripheral blood mononuclear cell fractions, specifically targeting non-naive T cells, regulatory T cells, and conventional CD4+ T cells.
What criteria defined patient eligibility in the screening trials?
Participants in the SUMMIT and ALPINE cohorts were current or former smokers aged 55 to 77 years who met specific risk thresholds calculated by lung cancer risk models, excluding individuals currently receiving treatment for active cancers.
Keep reading