In multivariate Cox regression cytoplasmic GPER expression remained significantly associated (P=0.023) with breast cancer survival when including the potential confounding factors of tumour size, tumour stage and grade, NPI value, ER, PgR and HER2 status and Lymph node status (with individual Kaplan–Meier statistics of P<0.001, P<0.001, P<0.001, P<0.001, P=0.002, P<0.001, P<0.001, P<0.001 respectively) (Table 2). Here, ERBB2 is linked to breast cancer.