MMP9 and peptic ulcer disease: Due to their pleiotropism, polymorphisms of the MMP9 genes play a key role in multiple biological pathways and therefore have been implicated not only in peptic ulcer [13, 73, present study], but also in cardiovascular diseases [60, 61] as well as a broad range of other disorders involving processes of synthesis and degradation of extracellular matrix: various cancers, including digestive [46–48, 74–76], glaucoma [27, 77, 78], and others [79–82].