In a study of 987 ER+/HER2− breast cancers, higher TIL levels were significantly associated with lymph node metastases (p = 0.003), high tumor grade (p < 0.0001), low ER levels (p < 0.0001), and high Ki67 levels (p < 0.0001) [18]. The gene discussed is ESR1; the disease is neoplasm.