Fig. 6: The inactivation of CD8⁺ T cells in MTC.

A Re-clustering of T cells is shown in the UMAP plot annotated with subpopulations. B Number of differentially expressed genes (DEGs) between MTC- and PTC- derived CD8⁺T cells, CD4⁺T cells, NK cells and ILCs. C Comparison of the scores for naive-like, cytotoxic and dysfunctional gene expression of CD8⁺ T cells between MTC and PTC. The boxplot illustrates the interquartile range in relation to the median, while the middle lines represent the median, and the lower and upper hinges denote the 25–75% interquartile range (IQR), with whiskers extending up to a maximum of 1.5 times IQR. Calculated by two-sided Wilcoxon rank-sum test. D Dot plot showing the expression of naive-like, cytotoxic and dysfunctional genes in CD8⁺ T cells of PTC and MTC. E Bar graph showing the proportions of T cell receptor (TCR) expansion levels in MTC and PTC. X represents the clonal size of the TCR clonotypes. F Scatter plot of cross-tissue clonal expansion analysis was shown for patients with tumor sample, adjacent normal thyroid tissue sample and blood sample. Dots were sized for blood clonal size and colored according to tissue expansion pattern. Equal cell proportions were indicated by diagonal lines, and the absence or presence of clones within compartments were separated by other lines. G Heatmap showing the distribution ratio of CD8⁺ T cell subpopulations in PTC and MTC, *p < 0.01. H Violin plot showing the gene scores of naive-like, cytotoxic and dysfunctional in differentially distributed subpopulations of CD8⁺ T cells. The box inside illustrates the interquartile range in relation to the median, while the middle lines represent the median, and the lower and upper hinges denote the 25–75% interquartile range (IQR), with whiskers extending up to a maximum of 1.5 times IQR. Calculated by two-sided Wilcoxon rank-sum test. I Density plot showed the distribution of CD8⁺ T cell subpopulations along the pseudo time trajectory (upper-left panel). Heatmap showed the changing gene expression over time (lower-left panel). Pathway enrichment analysis was displayed in a bubble plot showing the differential pathway activity of genes located at the beginning and end of the trajectory, respectively. The dot size represented gene counts and the color represented -Log10(p-value) (lower-right panel).