Rates of breast cancer vary greatly among countries, with incidence and mortality in wealthier, more industrialized nations exceeding those in lower-income countries by a factor of five or more. Until recently, breast cancer was rare in Mexico, a country formerly considered low-risk. Now, breast cancer is the most commonly diagnosed cancer among women in the more industrialized states in Mexico and those in the northern regions of the country. Epidemiological studies of breast cancer in the United States have provided only limited data specific to Hispanic/Latino women. A recent publication by our group shows that compared to white women in Arizona, Hispanic women are diagnosed with tumors that have a more aggressive pattern and less favorable prognosis.
The overall goal of this study is to conduct a binational multi-center collaboration to investigate whether epidemiological and clinical risk factors as well as standard and novel tumor markers, which predict for increased incidence and prognosis of breast cancer, differ between women in Mexico and Mexican-American women living in the US. It is presently unknown whether the increase in breast cancer occurrence that accompanies transition to a higher risk environment involves an increase in all types of breast cancer or if the increase is specific for certain tumor types with better or worse clinical prognostic features, as defined by their histopathological appearance and immunohistochemical markers. The population of women living on either side of the US-Mexico border presents an extraordinary opportunity to address these and other clinically important aspects of breast cancer occurring in women of Mexican descent.