Fig. 1: A time-resolved view of TNBC development in the Blg-Cre; Brca1^f/f; p53^+/− mouse model at single-cell level.

a Schematic overview of the experimental design. Mammary glands from 13 animals between 30 and 48 weeks of age as well as two fully developed tumours were prepared for scRNA sequencing after depleting dead cells. b UMAP of all samples, including wild-type controls, cells are coloured by cell type annotation. For the complete annotation see Supplementary Fig. 3b. c Principal component analysis computed on the pseudo-bulked, normalised and log-transformed counts from all samples of the Blg-Cre; Brca1^f/f; p53^+/− animals. Dashed lines highlight the boundaries of the four stages pre-malignancy and the tumour stage. The mean age in each stage is noted at the top of the plot (Stage 1: 36.6w [30–41], Stage 2: 40w [38–41], Stage 3 42.3w [33–48], Stage 4: 42w [38–46], Tumour: 47w [46–48]). d UMAP from b subsetted by the stages identified in c. Cells are coloured by cell compartments. Grey cells in the background represent cells from all samples not present at the stage of interest. Bars underneath the UMAPs represent the tissue composition at each stage. PC principal component.