To further elucidate the mechanism how HNF1B influences the cell cycle, we re‐explored and analysed the RNA‐seq data, and focused on Cyclin D1, which a key regulator of cell cycle (G1‐ phase) for both normal and tumour cells, is negatively regulated by HNF1B in prostate cancer cells. The gene discussed is HNF1B; the disease is Familial prostate cancer.