Porphyrins as urinary biomarkers for bladder cancer after 5-aminolevulinic acid (ALA) administration: The potential of photodynamic screening for tumors

Background Tumor biomarkers are commonly used for cancer screening and as indicators of treatment effects. We recently reported that urine porphyrin levels from tumor-bearing mice were elevated compared with those from normal mice after administration of 5-aminolevulinic acid (ALA). In the present study, we evaluated the use of urine samples from bladder cancer patients as tumor biomarkers. Methods ALA, 1.0g, was orally administered to 66 bladder cancer patients and 20 healthy adults. The urine concentrations of uroporphyrin I (UPI), uroporphyrin III (UPIII), coproporphyrin I (CPI), coproporphyrin III (CPIII), and total porphyrins were measured using High Performance Liquid Chromatography (HPLC) system. Results Almost all of the urinary porphyrin concentrations from the patients with bladder cancer were higher than those from healthy adults. Moreover, 8h after ALA administration, urinary UPI and CPI showed high sensitivity (100 for UPI and CPI) and specificity (96.4 for UPI and 91.4 for CPI). Conclusion These results indicate that the presence of urinary porphyrins after administration of ALA may function as tumor biomarkers. This method represents a possible new tumor screening method called photodynamic screening (PDS) using ALA-induced porphyrins.