An architectural map of the conserved HCC network at the systems level. (A) 228 HCC-related genes in EHCO collections are evolution conserved cross various species. EHCO collects 2906 HCC-related H. sapiens genes, of which 2,635 genes have M. musculus homologs (point by arrow) and 114 genes cannot find any homologs (point by node). Of 2635 M. musculus genes, there are 774 genes with C. elegans homologs and 324 genes have D. melanogaster homologs, but do not have C. elegans homologs (branch and point by arrow). In short, 228 genes are conserved from H. sapiens to S. cerevisiae. (B) Conserved HCC network. Among 139 overexpressed and evolutionary conserved HCC-related genes, 120 of them have at least one PPI record. 47 of them can interact with each other and constitute a network and 18 of them are query-also-hubs (red circle). (C) Evaluation of the essentialness of hubs. To evaluate the essentialness of hubs, 139 queries, 47 queries constituting of interaction network, and 18 query-also-hubs were subjected to search for the nonviable phenotype in their corresponding homologs in various model organisms, including C. elegans, D. melanogaster, and S. cerevisiae. (D) Evaluation of the feature of hub degree. The degree, which is referred to as number of interactions associated with a protein, is considered to be one of the features in determining the essentialness of hubs. 18 query-also-hubs, which have various degrees ranging from 2–7, were subjected to search for the nonviable phenotype in their corresponding homologs in S. cerevisiae. The relative ratio is shown.