# The Detection of Lung Cancer Cell Profiles in Mediastinal Lymph Nodes Using a Hematological Analyzer and Flow Cytometry Method

## TL;DR

This study shows how hematological analyzers and flow cytometry can quickly detect lung cancer cells in lymph nodes, improving cancer diagnostics.

## Contribution

This is the first study to demonstrate the feasibility of detecting tumor cells and their antigen expression in lymph nodes using hematological analyzers and flow cytometry.

## Key findings

- High expression of EpCAM, TTF-1, Ki67, cytokeratin, and HER was observed in detected cancer cells.
- Differences in antigen expression between NSCLC and SCLC were identified, including MUC-1, CD56, PD-L1, and others.
- Combined methods efficiently identified non-hematopoietic cancer cells with high fluorescence and metabolic activity.

## Abstract

The study highlights the importance of mediastinal lymph nodes (LNs) in lung cancer treatment and immune response activation. We used EBUS/TBNA to collect LN aspirates and analyzed them via a hematological analyzer and flow cytometry. The hematological analyzer detected highly fluorescent cells with high metabolic activity, while flow cytometry confirmed their non-hematopoietic origin. These combined methods efficiently identified cancer cells in LNs. Key findings include a high expression of markers like EpCAM, TTF-1, Ki67, cytokeratin, and HER, as well as differences between NSCLC and SCLC in antigens such as MUC-1, CD56, HLA-DR, CD39, CD184, PD-L1, PD-L2, and CTLA-4. This study is the first to demonstrate the feasibility of detecting tumor cells and their antigen expression in LNs using these techniques. This precise characterization of non-hematopoietic cells in LNs could significantly aid in identifying micrometastases and refining lung cancer diagnostics.

The presence of metastases in mediastinal lymph nodes (LNs) is essential for planning lung cancer treatment and assessing anticancer immune responses. The aim of the study was to assess LNs for the presence of neoplastic cells and evaluate lung cancer-selected antigen expression. LN aspirates were obtained during an EBUS/TBNA procedure. The cells were analyzed using a hematological analyzer and flow cytometry. It was possible to indicate the presence of cells characterized by high fluorescence connected with high metabolic activity using a hematological analyzer and to determine their non-hematopoietic origin using flow cytometry. Using these methods together, we detected very quickly a high proportion of cancer cells in LNs. We noticed that it was possible to determine a high expression of EpCAM, TTF-1, Ki67, cytokeratin, HER, and differences between non-small-cell (NSCLC) and small-cell lung cancer (SCLC) for the antigens MUC-1, CD56, HLA-DR, CD39, CD184, PD-L1, PD-L2 and CTLA-4 on tumor cells. We report, for the first time, that the detection of tumor cells in LNs with the expression of specific antigens is easy to evaluate using a hematological analyzer and flow cytometry in EBUS/TBNA samples. Such precise characteristics of non-hematopoietic cells in LNs may be of great diagnostic importance in the detection of micrometastases.