MMP11 and breast cancer: Specifically: 1) NEK2 is a constituent of the 11-gene Breast Cancer Index signature used to estimate recurrence (Zhang et al., 2013); and 2) MMP11 is a constituent biomarker of the 50-gene Prosigna (Parker et al., 2009), and 21-gene OncotypeDX (Cronin et al., 2007) signature panels, which are both used in estimating likelihood of recurrence.