Gremlin 1 (GREM1) is an inhibitor in the TGF-beta signaling pathway. The protein expression is found in many cancers and is thought to play important roles in uterine cervix, lung, ovary, kidney, breast, colon, pancreas, and sarcoma carcinomas. GREM1 and other BMP antagonists are important in the survival of cancer stroma survival and proliferation in some cancers. Thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human GREM1 and recombinant human BMP2. Briefly, GREM1 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to BMP2-coated microtiter wells and incubated for 1h at 37 ℃. Wells were washed with PBST and incubated for 1h with anti-GREM1 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 μL stop solution to the wells and read at 450nm immediately. The binding activity of recombinant human GREM1 and recombinant human BMP2 was shown in Figure 1，the EC50?for this effect is 0.1~0.562 ug/mL.