
In both healthy and diseased tissue, the spatial arrangement and structure of cells can oftentimes be as important as the cells themselves. For example, when assessing lung cancers, pathologists try to look at the overall grouping and structure of tumor cells (do they form solid sheets? Or do they occur in smaller, localized clusters?) to determine if the cancer belongs to specific subtypes which can have vastly different prognosis. Such spatial relationships between cells and other tissue structures can be modeled using graphs to capture tissue topology and cellular composition at the same time. Graph Neural Networks (GNNs) allow learning spatial patterns within these graphs that relate to other clinical variables, for example overexpression of genes in certain cancers.