CXCL9 and cancer: 3-HK and KYNA interactions in the PRE network identify groups of proteins such as CXCL13, IL-8, TIE2, ADGRG1, CCL20, and CXCL9 to be involved in Tie2 and SHP2 signaling with an inhibitory effect on Th1 differentiation (51–54) Interaction of Tie2, a tyrosine kinase receptor, with its ligand angiopoietin-1(Ang1), regulates angiogenesis which makes it an attractive target for cancer therapy (53).