ESR1 and cancer: The commonly used candidate predictors included age, stage of cancer, grade, tumor size, race, marital status, number of nodes, histology, number of positive nodes, primary site code, extension of tumor, behavior/behavior code, lymph node involvement, site-specific surgery code, number of primaries, radiation, received radiation, estrogen receptor (ER) status, and progesterone receptor (PR) status (see Table 4).