24Parts of East Asia have a very high upper tract urothelial carcinoma (UTUC) prevalence, and an 25 etiological link between the medicinal use of herbs containing aristolochic acid (AA) and UTUC 26 has been established. The mutational signature of AA, which is characterized by a particular 27 pattern of A:T to T:A transversions, can be detected by genome sequencing. Thus, integrating 28 mutational signatures analysis with clinicopathological data may be a crucial step toward 29 personalized treatment strategies for the disease. Therefore, we performed whole-genome 30 sequencing (WGS) of 90 UTUC patients from China. Mutational signature analysis via 31 nonnegative matrix factorization method defined three etiologically distinct subtypes with 32 prognostic relevance: (i) AA, the typical AA mutational signature characterized by signature 22, 33 had the highest tumor mutation burden, the best clinical outcomes; (ii) Age, an age-related group 34 featured by signatures 1 and 5, had the lowest weighted genome instability index score, the worst 35 clinical outcomes; and (iii) DSB, signature with deficiencies in DNA double strand break-repair 36 featured by signatures 3, the intermediate clinical outcomes. Additionally, the distinct AA subtype 37was associated with AA exposure, the highest number of predicted neoantigens and heavier 38 lymphocytes infiltrating. Thus, it may be good candidate for immune checkpoint blockade therapy. 39 Notably, we showed AA-mutational signature was also identified in histologically "normal" 40 urothelial cells. Thus, non-invasive urine test based on the AA-mutational signature could take 41 advantage of this "field effect" to screen individuals at increased risk of recurrence due to exposure 42 to herbal remedies containing the carcinogen AA. Collectively, the findings here may accelerate 43 the development of novel prognostic markers and personalized therapeutic approaches for UTUC 44 patients in China. 45 46 3