The most common mutations detected in urine at diagnosis were in the TERT promoter. In non-invasive BC, these mutations were related to high risk and grade (p<0.0001) as well as progression to muscle-invasive disease (p=0.01), whereas FGFR3 mutations were observed in low-grade BC (p=0.02) and patients with recurrences (p=0.05). The gene discussed is FGFR3; the disease is breast cancer.