Diagnostic leukapheresis reveals distinct phenotypes of NSCLC circulating tumor cells.

BACKGROUND: Circulating tumor cells (CTCs) hold immense promise for unraveling tumor heterogeneity and understanding treatment resistance. However, conventional methods, especially in cancers like non-small cell lung cancer (NSCLC), often yield low CTC numbers, hindering comprehensive analyses. This study addresses this limitation by employing diagnostic leukapheresis (DLA) to cancer patients, enabling the screening of larger blood volumes. To leverage DLA's full potential, this study introduces a novel approach for CTC enrichment from DLAs. METHODS: DLA was applied to six advanced stage NSCLC patients. For an unbiased CTC enrichment, a two-step approach based on negative depletion of hematopoietic cells was used. Single-cell (sc) whole-transcriptome sequencing was performed, and CTCs were identified based on gene signatures and inferred copy number variations. RESULTS: Remarkably, this innovative approach led to the identification of unprecedented 3,363 CTC transcriptomes. The extensive heterogeneity among CTCs was unveiled, highlighting distinct phenotypes related to the epithelial-mesenchymal transition (EMT) axis, stemness, immune responsiveness, and metabolism. Comparison with sc transcriptomes from primary NSCLC cells revealed that CTCs encapsulate the heterogeneity of their primary counterparts while maintaining unique CTC-specific phenotypes. CONCLUSIONS: In conclusion, this study pioneers a transformative method for enriching CTCs from DLA, resulting in a substantial increase in CTC numbers. This allowed the creation of the first-ever single-cell whole transcriptome in-depth characterization of the heterogeneity of over 3,300 NSCLC-CTCs. The findings not only confirm the diagnostic value of CTCs in monitoring tumor heterogeneity but also propose a CTC-specific signature that can be exploited for targeted CTC-directed therapies in the future. This comprehensive approach signifies a major leap forward, positioning CTCs as a key player in advancing our understanding of cancer dynamics and paving the way for tailored therapeutic interventions.

Pathologic responses in oligometastatic NSCLC patients treated with neoadjuvant immune checkpoint blockade with and without chemotherapy followed by surgery.

OBJECTIVES: Immune checkpoint inhibitors (ICI) have significantly improved outcome of patients with advanced NSCLC and recently also showed benefit in early-stage disease. Patients with oligometastatic disease (OMD) harbor limited metastases, resectable primary tumors and derive benefit from treatment with multimodal locally ablative and systemic therapy approaches. Nothing is known about feasibility and efficacy of neoadjuvant ICI in this setting. MATERIAL AND METHODS: We here provide data from a multicenter retrospective study comprising 13 patients with NSCLC and OMD (≤3 distant metastases) from 5 university medical centers in Germany who have been treated with neoadjuvant ICI alone (n = 4) or in combination with chemotherapy (CT) (n = 9) prior to resection of the primary tumor. We analyzed complete (pCR) and major pathological remission (MPR) rates. RESULTS: These data show that neoadjuvant immunotherapy applied mostly in combination with CT results in high rates of pCR and MPR (54 and 69%, respectively). Up to now, 85% of patients are free of progression with a median follow-up of 9 months (3-28 months). Single cell RNASeq analysis of tumor tissue from one patient treated with CT-ICI indicates a strong predominance of adaptive immune cell populations over a small minority of epithelial (tumor) cells. CONCLUSION: Neoadjuvant ICI with or without CT is a promising therapeutic concept in patients with OMD.