Elevated expressions of GDF15 and BMP4 were associated with poorer prognosis comparing the low expression cohort (122.64 months) in HER2 negative patients with HER2 positive group (P<0.01), which indicates that GDF15 and BMP4 tend to promote the progression of breast cancer in HER2 (+) patients. The gene discussed is ERBB2; the disease is breast cancer.