PGR and breast cancer: Moreover, it is strange that the expression of RSK2 is highest in basal-like breast cancer (TNBC), which is defined by the absence of the three main breast cancer biomarkers—i.e., a lack of expression of ER and PR and a lack of amplification or overexpression of HER2—and cooperates with poor prognosis and high risk of distant metastasis (Carey et al., 2010), but the OS, the potential of distant metastasis, and the lymph node metastases were more favorable in the RSK2 high-expression group in the basic data from microarray.