RT Journal Article SR Electronic T1 Automated Quantitative Measures of Terminal Duct Lobular Unit Involution and Breast Cancer Risk JF Cancer Epidemiology Biomarkers & Prevention JO Cancer Epidemiol Biomarkers Prev FD American Association for Cancer Research SP 2358 OP 2368 DO 10.1158/1055-9965.EPI-20-0723 VO 29 IS 11 A1 Kensler, Kevin H. A1 Liu, Emily Z.F. A1 Wetstein, Suzanne C. A1 Onken, Allison M. A1 Luffman, Christina I. A1 Baker, Gabrielle M. A1 Collins, Laura C. A1 Schnitt, Stuart J. A1 Bret-Mounet, Vanessa C. A1 Veta, Mitko A1 Pluim, Josien P.W. A1 Liu, Ying A1 Colditz, Graham A. A1 Eliassen, A. Heather A1 Hankinson, Susan E. A1 Tamimi, Rulla M. A1 Heng, Yujing J. YR 2020 UL http://cebp.aacrjournals.org/content/29/11/2358.abstract AB Background: Manual qualitative and quantitative measures of terminal duct lobular unit (TDLU) involution were previously reported to be inversely associated with breast cancer risk. We developed and applied a deep learning method to yield quantitative measures of TDLU involution in normal breast tissue. We assessed the associations of these automated measures with breast cancer risk factors and risk.Methods: We obtained eight quantitative measures from whole slide images from a benign breast disease (BBD) nested case–control study within the Nurses' Health Studies (287 breast cancer cases and 1,083 controls). Qualitative assessments of TDLU involution were available for 177 cases and 857 controls. The associations between risk factors and quantitative measures among controls were assessed using analysis of covariance adjusting for age. The relationship between each measure and risk was evaluated using unconditional logistic regression, adjusting for the matching factors, BBD subtypes, parity, and menopausal status. Qualitative measures and breast cancer risk were evaluated accounting for matching factors and BBD subtypes.Results: Menopausal status and parity were significantly associated with all eight measures; select TDLU measures were associated with BBD histologic subtype, body mass index, and birth index (P < 0.05). No measure was correlated with body size at ages 5–10 years, age at menarche, age at first birth, or breastfeeding history (P > 0.05). Neither quantitative nor qualitative measures were associated with breast cancer risk.Conclusions: Among Nurses' Health Studies women diagnosed with BBD, TDLU involution is not a biomarker of subsequent breast cancer.Impact: TDLU involution may not impact breast cancer risk as previously thought.