Figure 4.

Protein-protein interactions. Protein-protein interactions of identified (A) one-target anticancer genes and (B) two-target combinations. MCL clustering in the STRING database was applied to classify one-target enzymes into four classes and two-target enzymes to five classes. The first class contained nine enzymes in terpenoid backbone biosynthesis, the second class included five enzymes in metabolism of nucleotides, the third class had four enzymes in sphingolipid metabolism, and the fourth class included two enzymes in glycerophospholipid biosynthetic pathway. For the one-target case, RPIA in the pentose phosphate pathway was categorized in the first class, but that in the two-target case was considered to participate in glycosaminoglycan metabolism or central carbon metabolism.