ERBB2 and breast carcinoma: Since both MD and TDLU measures appeared to vary by breast cancer subtype in our analysis, we further addressed whether the associations between TDLU and MD measures varied by breast cancer subtypes by conducting multivariable-adjusted linear regression analyses in luminal A, luminal B (combining luminal B/HER2− and luminal B/HER2+), and non-luminal (combining HER2-enriched and TN) subtypes separately (Fig. 3).