Fig. 5: CD8⁺ T cells inversely correlate with platelets and predict metastasis-free survival.

a CXCL4 is selectively expressed in platelets (CD61⁺) and not by cultured 67NR and 4T1 cells, or the 67NR or 4T1 tumour cells isolated from BALB/c mouse harbouring these tumours, or by CD45⁺ fractions from these mice (n = 3). b Representative images of 67NR and 4T1 tumours grown in wild-type BALB/c mice stained with CD8a and CD61 (platelets). Scale bars: 200 µm. c Quantification of immunohistochemistry of 67NR and 4T1 tumours grown in wild-type BALB/c mice stained with CD8a and CD61(n = 20, analysed five areas per tumour, a total of four tumours). d Representative images of human triple-negative breast cancer tissues stained with CD8a and CD61 (platelets), scale bars, 200 µm. e Quantification of immunohistochemistry of human triple-negative breast cancer tissues stained with CD8a and CD61 (n = 68). f Negative correlation between platelets and CD8⁺ T cells in breast cancer using TCGA data. g Metastasis-free survival probability of patients with a low frequency of CD8⁺ T cells and high frequency of platelets (CD61⁺ cells) relative to breast cancer patients with a high frequency of CD8⁺ T cells and low frequency of CD61⁺ cells (n = 68) in breast tissue TMA. h Overall survival probability of breast cancer patients with high levels of CD8⁺ T cells and low levels of platelets compared to patients with low levels of CD8⁺ T cells and high levels of platelets (data obtained from TCGA, n = 1093). Quantitative data are mean ± SEM. Statistical analyses were performed by unpaired two-tailed Student’s t test for panels a and c or by log-rank test for panel e; ns indicates not significant, ^∗P ≤ 0.05, ^∗∗P ≤ 0.01, ^∗∗∗P ≤ 0.001, ^∗∗∗∗P ≤ 0.0001.