“…Multiple publications have identified an increased expression in PrCa [59,61,78,83,109,113,129,153,156], including positive associations with more advanced PrCa [67,75,84,103] [92,102] and poorer prognosis [35,77,89]. Others show no association [24,47,48,52,118], and a small number show negative associations [25,31,40] with PrCa progression, indicating that MMP-9 is not universally important. However, functional studies serve to confirm its significant role, particularly in PrCa spreading, with MMP-9 ablation repeatedly shown to decrease its invasion and/or migration [57,87,100,148].…”