A subset of 12-h urine samples from the Polish Breast Cancer Study (n = 717) containing control (n = 200), ER+/PR+ (n = 200), ER+/HER2 (n = 36), ER−/PR−/HER2+ (n = 81), and TNBC (n = 200) samples, including 500 breast cancer patients with tumor volume information, were analyzed (NCT00341458). This evidence concerns the gene ERBB2 and breast cancer.