IER3 and breast cancer: These genes clearly demonstrate the complexity of PRL effects, since PRL has the ability to suppress oncogenes (SOX4, FLT4, BCL6) and upregulate favorable prognostic markers (NTN4), while also upregulating genes involved in breast cancer growth and progression (AREG, WT1, IER3, EREG, TMC5, FN1, PTHrP).