The results suggested that SNHG4 knockdown dramatically inhibited cell proliferation (Fig. 7a, b and S4e) and colony formation (Fig. 7c) of PCa cells; in contrast, restoration of RRM2 by either let-7a knockdown or RRM2 reoverexpression rescued the hampered cell viability. This evidence concerns the gene SNHG4 and posterior cortical atrophy.