STK26 and metastatic malignant neoplasm in the lymph nodes: Additionally, lymph node metastasis was also observed to be strongly correlated with MST4 positivity with 67% (63/93 cases) of cases positive for lymph node metastasis, with only 22% positive for MST4 negative cases (Figure 6i), suggesting a role of MST4 in breast cancer metastasis.