Molecular Drivers of Onco<i>type</i> DX, Prosigna, EndoPredict, and the Breast Cancer Index: A TransATAC Study

In contrast to common understanding, RSs are determined more strongly by estrogen-related features and only weakly by proliferation markers. However, the EP, BCI, and particularly ROR scores are determined largely by proliferative features. These relationships help to explain the differences in the prognostic performance of the tests.