We retrospectively reviewed consecutive UC cases assessed with UCSF500....Patients with APOBEC (N=16) were compared with remaining 56 patients, comprised of 27 NHM patients and 29 patients with unknown TMB, showing APOBEC patients to have improved OS from diagnosis (125.3 months vs 44.5 months, p=0.05) but inferior OS for patients treated with chemotherapy (7.0 months vs 13.1 months, p=0.05)....APOBEC patients had shorter median PFS (4.3 vs. 7.0, p=0.01) and OS (7.0 vs 13.1, p=0.05) relative to the 15 Other patients (Figures 3D, E and Table 4). APOBEC patients were treated with cisplatin-based chemotherapy (4/5, 80%) and carboplatin-based chemotherapy (1/5, 20%)...