A multivariate Cox regression model was employed to assess the independent association of the cell subpopulations or radiogenomic signatures with overall survival (OS) or recurrence-free survival (RFS) while adjusting for the available clinical variables, including age, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and tumor size. The gene discussed is ESR1; the disease is neoplasm.