Our results only confirmed CTTN/MMPs signal pathway was valid, that the piR-19166 overexpression significantly suppressed the expressions of CTTN, MT1-MMP, MMP2 and MMP9 at mRNA and protein level in PCa cells, meanwhile, the knockdown of piR-19166 sharply promoted the expressions of CTTN, MT1-MMP, MMP2 and MMP9 in PCa cells. This evidence concerns the gene MMP9 and posterior cortical atrophy.