Additionally, our finding that positive p53 was found to be significantly associated both with high Wip1 and with low nuclear phospho-p38 only in the patients without lymph node metastasis, but not in those with lymph node metastasis, also suggests the possible involvement of the Wip1–p38–p53 pathway in indolent tumor progression (Fig. 3). Here, PPM1D is linked to metastatic malignant neoplasm in the lymph nodes.