In addition, since 88% of the primary tumors of patients presenting with low-grade NMI-BC carried a mutation in the FGFR3, RAS, and/or PIK3CA genes and 88% of the recurrences were mutant, the assays are a potential tool to detect recurrences in DNA obtained from urine samples during surveillance, which may contribute to a reduction in the number of cystoscopical examinations and is worth to investigate. Here, PIK3CA is linked to breast cancer.