STAT3 and breast cancer: In addition, several lines of evidence indicate that miR-874 functions as a tumour suppressor in various cancer types, including breast cancer, by targeting multiple genes, including protein phosphatase 1 catalytic subunit alpha (PPP1CA), histone deacetylase 1 (HDAC1), E2F transcription factor 3 (E2F3), signal transducer-activator of transcription 3 (STAT3), matrix metalloproteinase-2 (MMP-2), urokinase-type plasminogen activator (uPA), aquaporin-3 (AQP3), and ETS proto-oncogene 1 (ETS1)13,15–20, many of which positively regulate cell proliferation.