In cancer, MUC4 upregulation contributed to tumor proliferation, apoptosis, invasiveness and metastasis in an ErbB2-dependent and ErbB2-independent manner, and multiple signaling pathways are involved in its regulatory mechanisms, such as the PI3-kinase/Akt pathway, gp130/STAT3 pathway and Erk pathway [32–34]. The gene discussed is STAT3; the disease is neoplasm.