It provides breast recurrence scores, which help to predict the chance of metastasis and the likelihood of benefits from chemotherapy for early-stage breast cancer patients using the following criteria: ER-positive (and will be treated with hormone therapy), HER2 negative, negative or 1–3 positive lymph nodes, and a tumor size smaller than 5 cm [73,74,75]. The gene discussed is ERBB2; the disease is breast carcinoma.