Breast cancer is a poorly understood and under-studied disease in Hispanic/Latina women in the U.S. Breast cancer mortality rates are increasing in Mexico, particularly among younger women. Recruitment is underway in a binational study of breast cancer to accomplish two primary specific aims: 1) To compare profiles of tumor markers of prognostic and/or predictive importance (ER, PR, Her-2/neu, and Ki-67) and basal/luminal subtype markers between women in Mexico and Mexican-American women living in the U.S.; and 2) To assess whether differences in markers are more pronounced in postmenopausal women compared to premenopausal women and whether these are explained by factors associated with acquisition of lifestyles more representative of the U.S. We have recruited a total of 652 women (309 in the U.S. and 343 in Mexico) with very high participation rates (96% in the U.S. and 99% in Mexico). Preliminary data show some similarities but also some differences in various risk factors between the two countries. Women in Mexico were significantly older than those in the U.S. (53.8 vs. 48.7 years; p=0.001). Reproductive factor data show a similar age at menarche (12.8 vs. 12.8 years), age at menopause (46.5 vs. 45.3 years), and age at first pregnancy (23.6 vs. 22.3 years); however, the number of live births was higher in Mexico than the U.S. (3.7 vs. 3.2; p=0.007). Prevalence of family history of breast cancer was significantly higher in the U.S. (18.1%) than in Mexico (6.2%) (p=0.0001). Importantly, body mass index is high in both countries (29.1 in Mexico and 29.3 kg/m2 in the U.S.), which underscores the obesity problem in these patients. The proportion of triple negative breast tumors was higher in patients in Mexico compared to those in the U.S. (28.1 vs. 19.3%). However, this difference could reflect variation in performance in different pathology laboratories. We have demonstrated the feasibility of conducting a high quality binational investigation that includes the establishment of a multi-disciplinary team, including physicians, questionnaire administration, and collection and shipping of biospecimens from Mexico to the U.S. In addition, we have established state-of-the art infrastructure, including web-based informatics systems for data entry, management, and biospecimen tracking. Recruitment into the Ella study continues with the goal of enrolling 1,000 women (500 in the U.S. and 500 in Mexico), which will allow stratification to better understand the tumor subtypes in both countries.

Second AACR International Conference on the Science of Cancer Health Disparities— Feb 3–6, 2009; Carefree, AZ