MMP1 and metastatic malignant neoplasm in the lymph nodes: MMP1 expression was a better predictor factor of lymph node metastasis than well established pathological parameters (AUC: MMP1 = 0.751; histological grade = 0.672; perineural invasion = 0.596; tumor size = 0.376) (Figure 3B, Supplementary Table 5).