3.3 Lung cancer
Lung cancer is a highly malignant tumor of the bronchial mucosa or
glands in the lung and displays rapid growth and early metastasis.
Current SCS studies have revealed a central role played by cytotoxic and
effector T cells, NK cells, and different functional macrophage (Mφ)
subtypes in the immune microenvironmental heterogeneity of lung
adenocarcinoma and lung squamous cell carcinoma [65]. Wu et al.
[66] analyzed 42 tissue biopsies from patients with stage III/IV
non-small cell lung cancer (NSCLC). Those analyses identified the rare
cell types of follicular dendritic cells and T helper 17 cells in
tumors, and explained the correlation between tumor heterogeneity and
tumor-associated neutrophils. Li et al. [67] identified a cancer
cell subtype that deviated from the normal differentiation trajectory
and dominated the metastatic stage. The cells were obtained from 208,506
cells in normal tissue or from 44 patients with early-stage to
metastatic cancer. The investigators found that the normal resident
myeloid cell population was gradually replaced by monocyte-derived
macrophages and dendritic cells, and was accompanied by T-cell failure.
Overall, although there are still batch effects and difficulties with
clinical implementation, SCS has provided new insights into the
precision and accuracy of molecular cancer research on the tumor
microenvironment and cell heterogeneity, and has significantly improved
our understanding of cancer diagnostic stratification, biomarkers,
precision therapy, and prognosis.