For the DS created by DS-DC algorithm and for its complement (the set of proteins in the network that are not in the DS, ''non-DS''), we calculate their enrichments in BC genes, genes that are members of signaling pathways (SP), genes that are in the union of BC and SP genes (''BC or SP''), and genes that are both BC and SP genes (''BC and SP''). We find that the enrichments are much higher for the DS than for non-DS (Figure 9 A). Furthermore, the enrichments for the DS are statistically significant, with p-valuesƒ10 {11 , while for non-DS they are not, with p-values~1 (see Methods). Furthermore, we measure the enrichment in drug targets of BC and SP genes (i.e., of gene categories ''BC'', ''SP'', ''BC or SP'', and ''BC and SP'' defined above) that are in the DS, and of BC and SP genes that are not in the DS. If our hypothesis that the topological positioning of nodes in the DS indeed reflects their functional importance is correct, then BC and SP genes that are in the DS should contain more drug targets than BC and SP genes that are not in the DS, since proteins that are targeted by drugs are clearly important for normal cellular functioning. Indeed, we find that enrichments in drug targets are much higher for BC and SP genes that are in the DS than for BC and SP genes that are not in the DS (Figure 9 B) . Furthermore, these enrichments for the BC and SP genes that are in the DS are statistically significant, with p-valuesƒ10 {4 , while for SP and BC genes that are not in the DS they are not, with p-values~0:9998 (see Methods).