It is known that CYP causes interstitial cystitis through the following process: once CYP enters the body and is metabolized in the liver, an active antitumor drug and a toxic metabolite (acrolein) are produced, and acrolein is excreted in the urine through kidney, bladder and urethra, during this process acrolein induces bladder damage by injuring the bladder’s transitional epithelium50. The gene discussed is PPIG; the disease is interstitial cystitis.