CD4 and neoplasm: Similar to baseline, the fraction of proliferating (Ki67+) cells for all four immune cell subpopulations (CD3+, CD4+, CD8+, Foxp3+) at day 15 was numerically higher in basal-like tumours, while luminal tumours showed the lowest fraction of proliferating cells, although the difference was not statistically significant (Table 1, Fig. 3c, Supplementary Fig. 16c).