Alternatively, examining relative risks for HRT use within strata of each of the BMI tertiles separately, the relative risk for ER+PR+ breast cancer associated with current use of HRT was strongest for women within the lowest BMI tertile, and progressively weakened across BMI tertiles 2 and 3, respectively (Pinteraction < 0.001)(Table 5). Here, ESR1 is linked to breast carcinoma.