PTP4A1 and metastatic malignant neoplasm in the lymph nodes: The distribution of CTC subtypes is shown to be significantly related to the status of lymph node metastasis.[17,18] PTP4A1 was first identified as an early stimulus response factor involved in the regulation of cyclin phosphorylation and plays an important role in cell growth.[7] Previous studies have shown that microRNAs regulate cancer metastasis.