Page 17 - EJMO-9-2

Eurasian Journal of
Medicine and Oncology Single-cell sequencing for lung cancer

4.1. Single-cell sequencing in the discovery of lung molecular mechanisms involved in metastasis, although
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cancer biomarkers research on lung cancer remains limited. In the analysis
Metastasis is the leading cause of death in lung cancer. of CTCs obtained from NSCLC patients, single-cell
Circulating tumor cells (CTCs) shed into the bloodstream 10× Chromium successfully identified diverse CTC
contribute to metastasis. While most CTCs are eliminated phenotypes. The epithelial-like phenotype exhibited the
by immune cells, some evade immune detection, survive, expression of epithelial markers, along with markers of
and form metastatic foci, increasing patient mortality. proliferation (Ki67), inflammation (IL-1β), and immune
In 2007, CTCs were recognized as a tumor marker by response pathways. The mesenchymal/invasive phenotype
the American Society of Clinical Oncology. They play displayed markers such as vimentin, hypoxia-related genes,
a significant role in early diagnosis of tumors and are and genes associated with glycolysis. In addition, CTCs with
valuable for assessing treatment efficacy and prognosis. a mesenchymal/stem cell-like phenotype demonstrated
The examination of CTCs through innovative single-cell enrichment in genes such as ALDH13 and those linked
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methodologies allows for the continuous observation of to adipogenesis. Beyond CTCs as biomarkers for lung
tumors and facilitates a thorough comprehension of tumor cancer, chemokines such as CXC motif chemokine ligand
heterogeneity and the advancement of disease, thereby 1 (CXCL1) and CXC motif chemokine ligand 2 (CXCL2)
furnishing significant knowledge for early detection and have also emerged as potential biomarkers. Using primary
tailored treatment. 19,62,63 LUAD samples for scRNA-seq, researchers identified
CXCL1 and CXCL2 and validated these findings through
Single CTC-based sequencing is a promising minimally qRT-PCR, demonstrating a strong correlation between
invasive method for early cancer diagnosis. Xu et al. scRNA-seq and bulk RNA-seq data. In addition, an inverse
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performed WES on a single CTC from an early-stage lung relationship was observed between the expression levels of
cancer patient and identified six novel gene mutations these chemokines and specific microRNAs (miR-532-5p
[human immunodeficiency virus type 1 enhancer binding and miR-1266-3p) in LUAD. Notably, miR-532-5p was
protein 2 (HIVEP2), spermatogenesis associated 21 A detected in patients’ plasma, underscoring its potential
(SPATA21A), tubulin gamma complex component 2 as a minimally invasive biomarker for early lung cancer
(TUBGCP2), potassium voltage-gated channel modifier detection. Kagamu et al. identified a novel CD62L
low
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subfamily G member 1 (KCNG1), microRNA 4756 CD4 T-cell supercluster consisted of CXCR3 CCR4 -
+
+
(MIR4756), and acetylserotonin O-methyltransferase like CCR6 and CXCR3 CCR4 CCR6 cells, characterized
-
+
-
+
(ASMTL)], which reveal genetic information about tumors by high interleukin-7 receptor and TCF7 expression,
at the single-cell level. Su et al. investigated genomic using single-cell RNA sequencing. The presence of this
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alterations during chemotherapy by performing single-cell supercluster was significantly associated with PD-1
sequencing on CTCs from 48 SCLC patients. They found blockade efficacy, and its frequency in peripheral blood
that most genetic mutations present in tumor tissues were predicted patients’ PFS and OS. In addition, a specific
precisely identified in CTCs, demonstrating considerable subpopulation of CD4 T cells, known as Th7R cells, was
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DNA heterogeneity. This indicates that single-cell genomic identified as capable of recovering from a state of T-cell
analysis of CTCs is a valuable method for tracking genetic depletion and is usually accompanied by a longer survival
variations and monitoring disease progression in SCLC. in patients with non-reduced levels of such cells. While
Chang et al. found that CTCs in NSCLC patients receiving patients with a PD-L1 tumor cell positivity of ≥1% are the
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platinum-based chemotherapy carried cancer-driver main group to benefit from immune checkpoint inhibitor
mutations, including epidermal growth factor receptor therapy, some PD-L1-negative patients also benefit from
(EGFR) and TP53, which were shared with primary and/ immunotherapy, suggesting the presence of additional
or progressive tumors. CTCs also exhibited mutations in potential biomarkers. These findings further highlight the
genes related to cell cycle regulation and stem cell traits, critical role of CD4 T cells and their subpopulations in the
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such as SH3KBP1-binding protein 1 (SHKBP1), nuclear development of personalized immunotherapy strategies,
mitotic apparatus protein 1 (NUMA1), zinc finger protein providing important new directions for precision
143 (ZNF143), mucin-16 (MUC16), origin recognition treatment in advanced NSCLC. Zhong et al. studied
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complex subunit 1 (ORC1), paraoxonase 1 (PON1), and the characteristics of peripheral blood mononuclear cells
proline, glutamic acid, and leucine-rich protein 1 (PELP1). in lung cancer patients before and after pembrolizumab
These mutations were linked to drug resistance and treatment using single-cell RNA sequencing, discovering
metastasis in NSCLC. eight distinct cell types. The Cancer Genome Atlas (TCGA)
Transcriptomic analysis of individual CTCs using RNA data verified the link between the genes such as inhibitor
sequencing is a promising technology for elucidating the of DNA binding 2 (ID2), phosphatidylinositol-4,5-

Volume 9 Issue 2 (2025) 9 doi: 10.36922/ejmo.6883