Table 1: List of descriptors by feature type.

The phenotypic characterization of tumor cells is represented using a panel of descriptors. The red box indicates the descriptors that have been used to predict brain metastatic probability via machine learning.

Feature	Descriptor
Tumor cell	% extravasated into the niche
Tumor cell	Volume
Tumor cell	Sphericity
Tumor cell	Distance extravasated
Tumor cell	Live cell 2D migration
Micro-metastasis	Porosity
Micro-metastasis	Stromal interaction
Micro-metastasis	Age
Micro-metastasis	Growth rate
Stromal cell	Volume
Stromal cell	Distance from nearby cancer cells
Stromal cell	Distance from endothelial barrier
Stromal cell	Shape