The application and potential value of organizational transparency technology in the field of tumor microenvironment research.

Tumors are systemic and systemic diseases, resulting from a series of physiological processes such as metabolic disorders, inflammatory responses, immune responses, and neural infiltration. The growth of solid tumors occurs in a local environment known as the tumor microenvironment (TME), which promotes biological behaviors such as the proliferation, invasion, and metastasis of tumor cells. The components of TME are complex, mainly including infiltrating immune cells, cancer-associated fibroblasts (CAFs), endothelial cells, and other cells, in addition to tumor cells. At the same time, the extracellular matrix (ECM) is also an important component that maintains the composition of TME and participates in communication between various cells. The relationship between tumor cells and TME is interdependent, mutually promoting, antagonistic, and combative. Therefore, clarifying the composition and spatial distribution of various components of TME in complete tumor tissue is one of the important research directions for exploring the laws of tumor occurrence and development and for developing tumor treatment targets.
Traditional tumor tissue analysis relies on 2D tissue sections, which are difficult to provide information on the distribution of various types of cells within the entire three-dimensional tissue. Therefore, there is a need for an unbiased whole-tumor tissue analysis method to obtain pathological molecular information about tumors, to avoid false-negative reading results caused by missed readings. Whole-tissue clearing and 3D imaging is a technology that can explore the internal structure of tissues and the spatial relationships of cells, with great prospects and application potential in many fields, including embryonic biology, regenerative biology, tissue 3D printing, and especially tumor biology. There have been multiple reports on the application of 3D tissue clearing and imaging technology in TME research.
Cuccarese et al. successfully applied this technology to a lung adenocarcinoma model with injected tumor cells, visualizing the tumor boundary, infiltrating tumor-associated macrophages (TAMs), and the vascular system in TME. They analyzed the infiltration of TAMs in different tumor foci and found that the transport efficiency of nanotherapeutic drugs was related to the heterogeneous distribution of TAMs.
Whole-tissue clearing and 3D imaging not only enable the visualization of the entire tissue but can also be combined with other biological techniques, thereby allowing for an in-depth analysis of comprehensive information about tumor tissues by leveraging the advantages of multiple techniques. Rios et al. explored the cell dynamics of breast cancer tumorigenesis by labeling different tumor cell subpopulations and combining RNA sequencing, establishing a rapid, large-scale single-cell resolution 3D imaging process that can be used to study the potential mechanisms of tumor heterogeneity and EMT occurrence.