NTRK1 and infection: In the STAT3-related pathway, when cells are stimulated by inflammatory cytokines (IL-6, IL-22, etc.), growth factors [VEGF, EGF, hepatocyte growth factor (HGF), etc.] and other factors (UV, stress and infection), STAT3 is phosphorylated at Tyr 705 residue by JAK, intrinsic receptor tyrosine kinase and several non-receptor tyrosine kinases.