STAT3 and neoplasm: On one hand, lymphocyte, a kind of leukocyte which played a great role in adaptive immune responses, could be recruited from peripheral circulation system to tumor tissues after chronic inflammation and then activated transcription factor of inflammatory cell and tumor cell, such as NF‐ΚB, STAT3, and H1F1α, to promote the production of inflammatory mediators including chemokine and cytokines, such as IL‐6 which is mainly released by CD4 + T lymphocyte 3.