The study is partially consistent with our current observation that the EGF- and HRG-mediated ERK-AP-1 axis and EGR1 are central components of cell divergence of MCF-7 mammary tumor cells, and that the ERK signal is dynamically regulated by the transcriptional negative feedback through FHL2 or DUSP5, a MAPK phosphatase. This evidence concerns the gene DUSP5 and breast cancer.