Consistent with our previous findings that Nox4 is strongly upregulated in activated fibroblasts,18 significantly higher numbers of Nox4 mRNA‐expressing cells (0.73%, p < 0.001) and an abundance of densely stained clusters (denoting the presence of multiple transcripts/cell) were observed in PCa, particularly within the peritumoral stroma (Supporting Information, Fig. S2). Here, NOX4 is linked to posterior cortical atrophy.