TK1 and metastatic malignant neoplasm in the lymph nodes: In 2010, Chen et al. [26] examined the expression of Ki-67 and TK1 in 89 cases of breast cancer tissues and found that TK1 expression was associated with lymph node metastasis, TNM stage and histological grade, had nothing to do with patients’ age, but they also found that TKI there was no significant correlation with Ki-67 expression.