Critically, immunohistochemistry (IHC) of PCa bone metastasis specimens confirmed that MMP16 protein expression corresponded precisely to the exosomal SNHG1 gradient across experimental groups: C4-2B-sh-NC > C4-2B-sh-SNHG1 > RWPE-1 (Fig. 7G). This evidence concerns the gene MMP16 and posterior cortical atrophy.