MMP9 and ovarian cancer: Our current results point to the previously elucidated role of a2V in regulating matrix metalloproteinase-9 and extracellular acidification in ovarian cancer.39 In the mammary gland too, ductal elongation requires invasion into surrounding stroma.32 This invasion is brought about, in part, by the extracellular matrix-degrading enzymes such as matrix metalloproteinase-9,40 demonstrating a direct involvement of a2V in lumen formation and ductal invasion.