We quantitated the level of LCN2 in serum and urine level of treatment naïve, stage-II, human hormone receptor-negative breast cancer patients (n = 20 for serum and n = 20 for urine) and in cancer-free females (n = 12 for serum and n = 20 for urine) with or without smoking history (see Supplementary Data 3–5). Here, NR4A1 is linked to breast cancer.