MKI67 and lung cancer: It was recently reported that high expression level of TTK was correlated with the progression, clinical features and prognosis in various tumors.[31, 32] TTK exhibited significant high expression in lung cancer and ovarian cancer, and was associated with Cisplatin resistance.[27, 33] Meanwhile, TTK was also found to be up‐regulated in mantle cell lymphoma and diffuse large B‐cell lymphoma (DLBCL), and was associated with higher Ki‐67 index.[34] However, the expression level and clinical prognostic value of TTK have not been reported in TCL.