Although transient STAT3 phosphorylation and activation is essential for the development of immune cells such as T cells and B cells, cell growth and proliferation, cell migration, and cell death, chronic and hyper-activated STAT3 results in cancer-promoting inflammation, increased cell proliferation, cell survival, angiogenesis and metastases, and dysregulation of anti-tumor immunity [34,35]. The gene discussed is STAT3; the disease is cancer.