Abstract
BACKGROUND/AIM: Photodynamic diagnosis (PDD) with 5-aminolevulinic acid (5-ALA) can be used to detect bladder cancer lesions, but false-positive results without pathological malignancy could sometimes occur. However, a false-positive lesion might be the precancerous lesion. Telomerase reverse transcriptase (TERT) promoter mutations are commonly found in the tumors and urine of bladder cancer patients. TERT promoter mutations have been detected in normal mucosa and have been associated with subsequent bladder cancer development. In this study, we evaluated TERT promoter mutations in PDD false-positive samples in patients with non-muscle-invasive bladder cancer (NMIBC) who underwent PDD-assisted transurethral resection of bladder tumor (PDD-TURBT) after oral 5-ALA administration. MATERIALS AND METHODS: Among 117 patients who underwent PDD-TURBT for NMIBC, 18 NMIBC patients who had PDD with 5-ALA positive samples, which were pathologically diagnosed as no malignant diseases, were included in this study. TERT promoter mutations were evaluated in 24 PDD false-positive samples. Droplet digital PCR (ddPCR) was employed to detect C228T and C250T mutations in the TERT promoter region using genomic DNA. The relationship between mutations in the TERT promoter and recurrence of bladder tumors was assessed using the Kaplan-Meier survival analysis. RESULTS: TERT promoter mutations in PDD false positives were found in six (33.3%) patients. C228T mutation was found in five (27.8%) patients, and C250T mutation was found in one (5.5%) patient. TERT promoter mutations were significantly associated with the presence of two or more tumors (P=0.033) and with an European Organisation for Research and Treatment of Cancer (EORTC) risk score of 5 or higher (P=0.010) in PDD false-positive cases. Two-year recurrence-free survival (RFS) rate was 33.3% in TERT promoter mutation-positive cases and 50% in negative cases. There was no significant difference in RFS between TERT promoter-positive cases and negative cases (P=0.698). CONCLUSIONS: TERT promoter mutations were frequently found in PDD false-positive samples in patients with NMIBC who underwent PDD-TURBT. While limited in extent, PDD false-positive samples in patients with TERT promoter mutation positivity in the non-malignant urothelium might be precancerous lesions.