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Detailed resolution analysis reveals spatial T cell heterogeneity in the invasive margin of colorectal cancer liver metastases associated with improved survival

View Article: PubMed Central - PubMed

ABSTRACT

On a broader scale, T cell density and localization in colorectal cancer liver metastases have prognostic and predictive implications. As T cell distribution at higher resolutions has not been fully investigated, a detailed resolution analysis of T cell distribution was performed. Patient tissues were divided into 10 µm distance classes between the tumor border and adjacent normal liver. Thereby, distinct density patterns of T cell localization in relation to the malignant tissue could be detected. At a distance of 20 to 30 µm to the tumor, a decrease of CD3 T cells is common. Within this area, cytotoxic Granzyme B and CD8+ T cells were found to be significantly reduced as well as CD163 macrophages were increased and identified to be in close contact with T cells. Our data suggests a physical or functional border within this region. Survival analysis revealed improved overall survival in patients with high T cells numbers at the direct tumor border. Interestingly, the decreased T cells in the 20 to 30 µm region were also found to be significantly associated with improved survival. Consequently, the detailed localization of T cells, despite blockade, could be associated with improved clinical outcome. The high-resolution analysis represents new insights into relevant heterogenous T cell distributions especially related to clinical responses. As the paradoxical observation of localization-dependent prognostic relevance of T cell densities is only detectable by detailed spatial analyses, this investigation of spatial profiles at higher resolutions is suggested as a new biomarker for survival and response to therapies.

No MeSH data available.


Heatmap based on unsupervised clustering encompassing randomly selected single fields from all 36 patients. Color code indicates clustering of patients according to their relative T cell densities within single distance classes.
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f0003: Heatmap based on unsupervised clustering encompassing randomly selected single fields from all 36 patients. Color code indicates clustering of patients according to their relative T cell densities within single distance classes.

Mentions: As shown in Fig. 2, the distribution of CD3 cell densities obviously varied between the different distance classes (Kruskal–Wallis test, p = 0.0001). The statistically significant differences between adjacent distance classes are marked by asterisks (post-hoc Mann–Whitney U tests). It was observed that in the 20–30 µm distance class median T cell densities significantly decreased below 100 cells/mm2, whereas in the distance classes closer than 20 µm and further away than 30 µm from the tumor epithelium median densities higher than 150 cells/mm2 were found. To identify patterns of T cell densities, unsupervised clustering was performed. To avoid possible bias due to different lengths of the invasive margin between different patients, we randomly selected one single field from each patient for further pattern analysis. The clustering analysis revealed distinct groups as shown in Fig. 3 (non-informative distance classes were removed stepwise, informative distance classes shown). The adjacent distance classes 10–20 µm and 20–30 µm clustered, whereas the most proximal distance classes (< 10 µm) and the classes with the highest distance from the tumor epithelium (90–100 µm) were found to be least related to the 20–30 µm distance classes. Furthermore, clustering of patients according to their T cell densities within single distance classes was observed. Survival analysis comparing patients with high and low CD3 T cell densities within each distance class resulted in a significant prolongation of OS for patients with high CD3 cell numbers in the most proximal distance class (< 10 µm), while in the 20–30 µm region a significant prolongation of survival for patients with low T cell numbers was observed (Fig. 4). No significant differences between high and low T cell infiltrates were found in all other distance classes.Figure 2.


Detailed resolution analysis reveals spatial T cell heterogeneity in the invasive margin of colorectal cancer liver metastases associated with improved survival
Heatmap based on unsupervised clustering encompassing randomly selected single fields from all 36 patients. Color code indicates clustering of patients according to their relative T cell densities within single distance classes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384380&req=5

f0003: Heatmap based on unsupervised clustering encompassing randomly selected single fields from all 36 patients. Color code indicates clustering of patients according to their relative T cell densities within single distance classes.
Mentions: As shown in Fig. 2, the distribution of CD3 cell densities obviously varied between the different distance classes (Kruskal–Wallis test, p = 0.0001). The statistically significant differences between adjacent distance classes are marked by asterisks (post-hoc Mann–Whitney U tests). It was observed that in the 20–30 µm distance class median T cell densities significantly decreased below 100 cells/mm2, whereas in the distance classes closer than 20 µm and further away than 30 µm from the tumor epithelium median densities higher than 150 cells/mm2 were found. To identify patterns of T cell densities, unsupervised clustering was performed. To avoid possible bias due to different lengths of the invasive margin between different patients, we randomly selected one single field from each patient for further pattern analysis. The clustering analysis revealed distinct groups as shown in Fig. 3 (non-informative distance classes were removed stepwise, informative distance classes shown). The adjacent distance classes 10–20 µm and 20–30 µm clustered, whereas the most proximal distance classes (< 10 µm) and the classes with the highest distance from the tumor epithelium (90–100 µm) were found to be least related to the 20–30 µm distance classes. Furthermore, clustering of patients according to their T cell densities within single distance classes was observed. Survival analysis comparing patients with high and low CD3 T cell densities within each distance class resulted in a significant prolongation of OS for patients with high CD3 cell numbers in the most proximal distance class (< 10 µm), while in the 20–30 µm region a significant prolongation of survival for patients with low T cell numbers was observed (Fig. 4). No significant differences between high and low T cell infiltrates were found in all other distance classes.Figure 2.

View Article: PubMed Central - PubMed

ABSTRACT

On a broader scale, T cell density and localization in colorectal cancer liver metastases have prognostic and predictive implications. As T cell distribution at higher resolutions has not been fully investigated, a detailed resolution analysis of T cell distribution was performed. Patient tissues were divided into 10&nbsp;&micro;m distance classes between the tumor border and adjacent normal liver. Thereby, distinct density patterns of T cell localization in relation to the malignant tissue could be detected. At a distance of 20 to 30&nbsp;&micro;m to the tumor, a decrease of CD3 T cells is common. Within this area, cytotoxic Granzyme B and CD8+ T cells were found to be significantly reduced as well as CD163 macrophages were increased and identified to be in close contact with T cells. Our data suggests a physical or functional border within this region. Survival analysis revealed improved overall survival in patients with high T cells numbers at the direct tumor border. Interestingly, the decreased T cells in the 20 to 30&nbsp;&micro;m region were also found to be significantly associated with improved survival. Consequently, the detailed localization of T cells, despite blockade, could be associated with improved clinical outcome. The high-resolution analysis represents new insights into relevant heterogenous T cell distributions especially related to clinical responses. As the paradoxical observation of localization-dependent prognostic relevance of T cell densities is only detectable by detailed spatial analyses, this investigation of spatial profiles at higher resolutions is suggested as a new biomarker for survival and response to therapies.

No MeSH data available.