TNIK, or Traf2- and Nck-interacting kinase, is a member of the STE20 family with serine/threonine kinase activity. Its cellular localization is mainly in the nucleus and cytoplasm. TNIK plays a critical role in the Wnt/β-catenin signaling pathway, influencing cell proliferation and differentiation by regulating the transcriptional activity of β-catenin. The gene expression of TNIK is specific to various tissues, especially high in the brain and tumor cells. Mutations or overexpression of the TNIK gene are associated with the development and progression of various cancers, making it a potential target for cancer therapy.