ARNT and breast cancer: In conclusion, quantitative vascular US features including the vascular index on Microvascular US and the peak intensity, mean transit time, and area under the time-intensity curve on CEUS were associated with frequent mutations in ERBB2, KDR, PDGFRA, ARNT, and FGFR2. We speculate that vascular US examination may indicate the altered vascular microenvironment of breast cancer probably resulting from these genetic changes, and may provide surrogate markers that could be useful when making decisions about treatment and predicting the prognosis of breast cancer.