PTK2 and metastatic malignant neoplasm in the lymph nodes: Additional key correlations were observed with SPARC (ρ=0.36, p < 0.001), which phosphorylates focal adhesion kinase (FAK) to stimulate tumor cell invasion [64], and MMP9 (ρ=0.32, p < 0.001), a matrix metalloproteinase associated with extracellular matrix (ECM) degradation, lymph node metastasis, and poorer survival outcomes [65, 66].