RNF40 and breast carcinoma: A Kaplan–Meier analysis revealed that low levels of RNF40 mRNA are significantly correlated with poor relapse-free survival in all breast cancer patients (Fig. 2A), but high levels of RNF40 mRNA are correlated with poor relapse-free survival in a subtype of progesterone receptor (PR)-negative breast cancer patients (Fig. 2B).