Table 1. Dataset summary.

	Number of slides	Pleomorphism grade distribution (I, II and III)	Total number of manually segmented nuclei	Average number of manually segmented nuclei per slide
Subset A	21	8; 8; 5	2191	104.3 (±12.2)
Subset B	18	1; 10; 7	2073	115.2 (±12.2)

Representative regions from Subset A were used for tuning of parameters during the development of the segmentation procedure. Representative regions from Subset B were used for an independent validation of the chosen parameters. From each slide, approximately 100 representative nuclei were manually segmented with systematic random sampling.