TIMP1 and ovarian benign neoplasm: Interestingly, several studies have shown a significantly lower level of TIMP-1 immunohistochemical protein staining in invasive ovarian cancer samples compared to borderline and benign ovarian tumours [32,33], while one study [20] found a higher concentration of TIMP-1 (by ELISA technique in tissue homogenates) in both malignant, borderline and benign tumours compared to the concentration in normal ovaries which underlines the generally increased amount of TIMP-1 protein in ovarian tumours regardless of tumour invasiveness.