As Nox4 is constitutively active and primarily regulated at the mRNA level,15, 16 we utilized in situ hybridization (ISH) on prostate tissue sections and a PCa tissue microarray (TMA) to identify the cellular origin and semi‐quantify prostatic Nox4 mRNA levels using a highly specific assay with single mRNA transcript sensitivity (Supporting Information, Fig. S1).29 Nox4 mRNA was detected at low levels in both epithelial and stromal cells of the benign prostate (0.07% of cells in benign areas showed 1–2 mRNA transcript signals). The gene discussed is NOX4; the disease is posterior cortical atrophy.