ILC differs from IDC in many respects; for example, ILC is more multifocal and bilateral and is associated with a larger tumor size, lower histological grade, higher expression of estrogen receptor (ER) and progesterone receptor (PR), lower expression of human epidermal growth factor receptor 2 (HER2) and the loss of E-cadherin expression7–14. The gene discussed is ESR1; the disease is neoplasm.