MMP9 and hydrops fetalis: Among the list of proteins with known associations with HF, the following proteins were included in this top ranking: matrix metalloproteinase 2 (MMP2), chromogranin B (CHGB), collagen type II alpha 1 (COL2A1), tumor necrosis factor (ligand) superfamily member 11 (TNFSF11), matrix metalloproteinase 9 (MMP9) and tumor necrosis factor (TNF).