Single-Cell Analysis Reveals Characterization of Infiltrating T Cells in Moderately Differentiated Colorectal Cancer

Objective This study aimed to characterize the tumor-infiltrating T cells in moderately differentiated colorectal cancer. Methods Using single-cell RNA sequencing data of isolated 1632 T cells from tumor tissue and 1252 T cells from the peripheral blood of CRC patients, unsupervised clustering analysis was performed to identify functionally distinct T cell populations, followed by correlations and ligand-receptor interactions across cell types. Finally, differential analysis of the tumor-infiltrating T cells between colon cancer and rectal cancer were carried out. Results A total of eight distinct T cell populations were identified from tumor tissue. Tumor-Treg showed a strong correlation with Th17 cells. CD8(+)T(RM) was positively correlated with CD8(+)IEL. Seven distinct T cell populations were identified from peripheral blood. There was a strong correlation between CD4+T-N and CD4+blood-T-CM. Colon cancer and rectal cancer showed differences in the composition of tumor-infiltrating T cell populations. Tumor-infiltrating CD8(+)IEL cells were found in rectal cancer but not in colon cancer, while CD8(+) T-N cells were found in the peripheral blood of colon cancer but not in that of rectal cancer. A larger number of tumor-infiltrating CD8(+) Tex (88.94%) cells were found in the colon cancer than in the rectal cancer (11.06%). The T cells of the colon and rectal cancers showed changes in gene expression pattern. Conclusions We characterized the T cell populations in the CRC tumor tissue and peripheral blood.

Automated summary

This study characterized tumor-infiltrating T cell populations in colorectal cancer using single-cell RNA sequencing data, revealing distinct T cell subgroups in tumor tissue and peripheral blood. Differences in tumor-infiltrating T cell populations between colon cancer and rectal cancer were identified, with changes in gene expression patterns observed in both cancer types.