摘要Objective:Lymphovascular invasion(LVI)is a crucial step in metastasis and is closely associated with poor prognosis in patients with breast cancer.However,its clinical and molecular characteristics remain insufficiently defined.We aimed to identify molecular targets for LVI-positive(LVI+)breast cancer and predict patient prognosis via the analysis of genomic variations using targeted sequencing.Methods:We established a large-scale targeted sequencing cohort of 4,079 breast cancer samples,which included 3,159 early-stage and locally advanced patients with available LVI statuses.Comparisons of somatic mutation frequencies and germline pathogenic/likely pathogenic(P/LP)mutation frequencies,mutational signature analyses,and mutual exclusivity and co-occurrence analyses were performed to identify key genomic features involved in LVI+patients.Additionally,Kaplan-Meier survival analysis was conducted to further explore the prognostic value of co-mutations in LVI+cases.Results:We observed that LVI+patients with the hormone receptor-positive/human epidermal growth factor receptor 2-negative(HR+/HER2-)and triple-negative breast cancer(TNBC)subtypes exhibited worse disease-free survival.Notably,HR+/HER2-and HER2+breast cancer patients with LVI displayed distinct genomic features compared with LVI-tumors.Specifically,LVI+HR+/HER2-tumors exhibited greater frequencies of somatic mutations in TP53 and ESR1,germline BRCA2 P/LP variations,and an enrichment of clock-like single-base substitution(SBS)1 mutational signatures.In contrast,LVI+HER2+tumors demonstrated a higher incidence of somatic PIK3CA mutations and increased activity of the apolipoprotein B mRNA editing enzyme catalytic polypeptide(APOBEC)-associated SBS2 signature.Furthermore,we revealed that the co-mutation of TP53 and NF1 could serve as a potential prognostic marker for LVI+HR+/HER2-patients.Conclusions:Our findings provide a comprehensive overview of the genomic characteristics of LVI in breast cancer,thereby offering insights that may help in refining precision treatment strategies for LVI+breast cancer patients.