Edges (or links) can be either undirected, in the case of co-occurrences, or directed, when predicates are used.2 Figure 1 shows an example, where a discovery is present in the statement “Neuronal ApoE upregulates MHC-I expression to drive selective neurodegeneration in Alzheimer’s disease” (PMID 33958804). This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.