MMP9 and neoplasm: Furthermore, 4-PBA was unable to enhance the expression of matrix metalloproteinase MMP-2 and MMP-9 inhibited by DIM compared to those treated with 4-PBA alone as shown in Figure 8B. These data suggest that the anti-tumor effect of DIM is mediated by inhibition of ER-stress mediated EMT of Hep3B and Huh7 cells.