NR4A1 and breast carcinoma: Its higher cell proliferation rate is related to worse prognosis when compared to luminal A. (7) Overexpression of HER2 occurs in 10 to 15% of breast cancers, is frequently hormone-receptor-negative, and has the second worst prognosis when compared to patients who do not show this gene amplification, although molecularly targeted therapy improves the prognosis.