Analysis of triangular motifs in protein interaction networks and their implications to protein ages and cancer genes

Proteins interact with each other to regulate their functionality and localisation. The accumulated protein interaction evidences are represented by protein interaction network through a graph abstraction. Topological properties of protein interaction networks have been explored to characterise proteins and predict undiscovered interactions. Meanwhile, many researchers have tried to explain how protein interaction network is formed through evolutionary process. Moreover, the topological properties of protein interaction network are reported to have relationship with cancer-related genes. In this paper, we construct a weighted human protein interaction network based on triangles in protein interaction network and show that there is relationship between triangles in protein interaction network and phylogenetic age of proteins. We also show that triangles in protein interaction network are related to cancer-related genes.