Toxicity prediction revealed that 4-NP exhibits significant activity across several clusters, including estrogen receptor (ER), estrogen receptor ligand binging domain (ER-LBD) and matrix metalloproteinase (MMP), all of which may be implicated in the pathogenesis of breast cancer (Fig 1) and all ProTox -predicted toxicological data for 4-NP have been deposited in Supporting Information S1 Table. The gene discussed is ESR1; the disease is breast carcinoma.