Figure 4. Correlation of PNPO expression with progesterone receptor (PR) expression. (A) Detection of the correlation of PNPO mRNA expression with the expression of ER, PR and HER2 mRNA in breast IDC tissues by qRT-PCR (n = 30 each). (B) Expression of PR and PNPO proteins in IDC tissues of two patients with a low level of PNPO (left sample) and the high level of PNPO (right sample) detected by Western blot. (C) Correlation of PNPO protein expression with PR protein expression in IDC tissues (n =30). (D) Effect of PNPO knockdown by shRNA on PR mRNA expression detected by qRT-PCR. Breast non-cancerous cells (MCF-12A) and cancerous cells (MCF-7 and MDA-MB-231) were treated with PNPO-shRNA (shPNPO) and its negative control (NC). A total PR (PR-A/B) and a B-type PR (PR-B) were detected by qRT-PCR (n = 3). * P < 0.05. (E) Effect of PNPO knockdown by shRNA on PR protein expression detected by Western blot in MCF-12A, MCF-7, and MDA-MB-231 cells.