ESR1 and neoplasm: ER negativity (Z = -2.166, P = 0.031), higher nuclear grade (Z = 6.792, P = 0.034), and higher Ki-67 index (≥20%) (Z = -2.322, P = 0.020) were significantly associated with higher VI value, whereas the tumor size, PR status, HER-2 status, histology, axillary lymph node metastasis, and TNM stage were not associated with VI value significantly (Table 1).