Abstract 1783: Heterogeneity of triple negative breast cancer across race and ethnicities: Indian women at higher risk for early onset breast cancer

Breast cancer is a heterogeneous disease with several subtypes presenting various morphological and molecular features, and response to therapy. While targeted therapies are available for estrogen receptor positive and HER2-positive breast tumors, triple-negative breast cancer (TNBC) which are negative for ER, progesterone receptor PR and HER2 receptors lack suitable targeted therapies. TNBC is one of the most aggressive breast cancer subtypes and poses a clinical challenge as they lack suitable targeted therapies. While a majority of breast cancer patients in the US are postmenopausal, more than 80% of Indian patients are younger than 60 years of age, with median age being 40-55, presenting with larger tumor size, poor tumor grade, and low rates of hormone-receptor positive status. Literature review suggests that none of the standard risk factors for breast cancer had any significant associations for the early onset breast cancers among Indian women. Recent studies on breast cancer subtypes across culture and geographical regions in India have indicated that incidence of early onset breast cancer, TNBC in particular is rising at alarming rates among Indian women. The interaction of race and ethnicity with age, molecular profiles and lifestyles has contributed significantly to the heterogeneity of TNBC breast cancer. The purpose of this study is to conduct a systematic literature review to identify factors that may increase risk for breast cancer among young Indian women. Methods: All the major databases including Web of Science and PubMed were used to search the literature for early onset breast cancer among Indian women. In a study that analyzed molecular subtypes in early onset breast cancer among various races that included Indian, Chinese, non-Hispanic White (NHW), African American (AA), and Hispanic women, incidence of TNBC was significantly higher (p = 0.0369) with early onset (40 years and younger) in Indian women. Incidence of HER2 over-expression subtype was also highest among Indian women. Conclusion: Early onset breast cancer is increasing rapidly among Indian women, along with obesity and diabetes. It is suggested that epigenetic factors that include sedentary lifestyles, lack of exercise, fatty diets and increasing obesity with underlying molecular mechanisms may contribute to early onset breast cancer among Indian women. Future studies that focus on racial and ethnic differences in genetic, reproductive, lifestyle and environmental exposures of TNBC pathways will offer unique biomarkers, targeted therapies and clinical trial design leading to personalized medicine. Citation Format: Padma P. Tadi Uppala, Maheswari Senthil, Utkarsh P. Patel, Sharon Lum, Carlos Garberoglio, Larry Beeson, John Morgan. Heterogeneity of triple negative breast cancer across race and ethnicities: Indian women at higher risk for early onset breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1783.