MMP9 and breast cancer: SPHK1 had shortest paths of 2 across MMP-2, MMP-9, and ABCG2, whereas shortest path of 1 with ABCC1. Similarly, CERK also had shortest path length of 2 across MMP-2, MMP-9, ABCG2, and ABCC1. CERK was functionally close with other candidates, indicating it to be playing major role in maintaining the regulatory interactions during breast cancer.