ANGPT2 and ovarian serous tumor: The level of Tie-1 expression was moderately, but significantly, correlated with its ligand Ang-2 IRS (r = 0.5, p < 0.001) in primary serous ovarian tumors, and the correlation was also significant with other histological types (IRS r = 0.3, p = 0.001; PP r = 0.4, p <0.001).