The ultrasound-guided breast biopsy revealed an infiltrating ductal carcinoma of grade 2 in the right breast, with estrogen receptor (ER) 90%, progesterone receptor (PgR) 90%, human epidermal growth factor receptor 2 (HER2) 2+, in situ hybridization not amplified, and a Ki 67 index of 28%. The gene discussed is ESR1; the disease is invasive ductal breast carcinoma.