In this analysis, seven classic clinicopathologic features [age, tumor size, nodal status, grade, estrogen receptor (ER) level, progesterone receptor (PgR) level and Ki-67 expression level] were combined into a single continuous value named composite risk (i.e., the Regan risk score), which functions as a tool to stratify patients according to their differences in outcomes between various ET combinations (35). Here, ESR1 is linked to neoplasm.