Christensen et al. [46] also detected ctDNA in patients with NMIBC and MIBC, but used a targeted approach with ddPCR assays to detect three hotspot mutations in PIK3CA (E545K) and FGFR3 (S249C, Y373C), first in tumour tissue and then in plasma and urinary supernatant. This evidence concerns the gene PIK3CA and neoplasm.