(A) CSBs extend the signaling proteins to cancer proteins. (B) Linked cancer types of CSBs. (C) Known anti-cancer drugs targeted on the proteins for signaling pathways, CSBs, and cancer. (D) Extended proteins by CSBs are more likely to be targeted by anti-cancer drugs than non-extended ones (Signaling proteins: P<10−5, Cancer proteins: P<10−14, Fisher’s exact two-tailed test). (E) The overall effects on protein sets evaluated by E-scores (see Supplementary Methods for details). For known anti-cancer drugs, they have significantly higher effects on cancer protein set than those of signaling pathways and CSB proteins (P<10−20, Mann–Whitney U test).