Cancer genomics research on tumor clonality and liquid biopsy

Most bladder cancer (BC) cases are non-muscle-invasive BC (NIBMC), which is rarely lethal. However, nearly one-fifth of NMIBC cases progress to muscle-invasive BC (MIBC), which shows a 5-year overall survival rate of 50%.

Cytology is widely conducted for diagnosis of urothelial bladder cancer; however, its sensitivity is still low. Recent studies show that liquid biopsies can reflect tumor genomic profiles. I aim to investigate whether plasma or urine is more suitable for detecting tumor‐derived DNA in patients with early‐stage urothelial bladder cancer. Targeted sequencing of 71 genes was carried out using a total of 150 samples including primary tumor, urine supernatant, urine precipitation, plasma and buffy coat from 25 patients with bladder cancer and five patients with cystitis and benign tumor. I compared mutation profiles between each sample, identified tumor‐identical mutations and compared tumor diagnostic sensitivities between urine and conventional cytology. I would like to present the data that urine is an ideal liquid biopsy for detecting tumor‐derived DNA and more precisely reflects tumor mutational profiles than plasma. Genomic analysis of urine is clinically useful for diagnosis of superficial bladder cancer at early stage.