Detecting pathway relationship in the context of human protein-protein interaction network and its application to Parkinson's disease.

•Detecting the pathways relationship is critical to study the molecular mechanism of disease.•A pathway can be represented as a gene module in the PPI network.•Pathway relationship can be measured based on their distribution in the PPI network.•The pathways can be linked into a network by their pairwise relationship.•The new method can reveal pathway relationship for complex diseases like Parkinson’s disease.