Thus, we comparatively studied the serum protein profile of breast invasive ductal carcinoma with a lower risk of recurrence (LN-ER/PR+Her2-; n=50) and those with a higher risk of recurrence (LN+ER/PR-Her2+; n=50) by proteomics, and then proposed that serum sCD14 is a potential biomarker for predicting recurrence of LN+ER/PR-Her2+ status breast cancer. This evidence concerns the gene ESR1 and invasive ductal breast carcinoma.