Fig. 6: The expression of SAMD4b influenced PD-L1 and thus the immune escape of tumour cells from naive CD29+CD8+ T cells.

a The tSNE plot of unsupervised clustering of T cells and NK cells. b CD8+ T cells (CD8 TRBC1, CD8 NR4A1, CD8 NR4A2 and CD8BRCA1) were enriched in tumour tissues of the low-SAMD4B-expression group. c CD8 T cells were significantly enriched in the low-SAMD4B-expression group in breast cancer and colon cancer samples. d The pseudotime analysis showed that CD8 RMP2 cells occurred at the beginning of the trajectory path, whereas CD8 NR4A2 cells were found at a terminal state. e The exhausted signature was upregulated, whereas the cytotoxic signature had no obvious down- or upregulation trend. f The transcriptional changes associated with transitional states were investigated, and the CD8+ T-cell clusters could be categorized into 3 phases. g DEG analysis showed that ITGB1 (CD29) was the top upregulated gene in CD8+ T cells in the low-SAMD4B-expression group. h In CD8+ and CD8+ naive T cells, the expression of ITGB1 (CD29) showed a significant positive correlation with PDCD1. i PD-L1, CK18 and SAMD4B had a colocalization relationship, and PD1 was colocalized with CD29, CD3 and CD8. The low-SAMD4B-expression samples contained more CD29+CD8+ T cells (j) in the HCC retrospective cohort, and the high expression of CD29+CD8+ T cells was associated with a worse prognosis (k). Student’s t test (level of significance: **, P < 0.01; *, P < 0.05; ns, P > 0.05).