We are working with French physician and social epidemiologist Pierre Chauvin (INSERM, Sorbonne) to move beyond projects that rely on data collected at the cité level (an administrative unit that is bigger than a neighborhood, but smaller than a city) to allow us to compare immigrant/refugee neighborhoods to non-immigrant/refugee neighborhoods within the cite to identify mortality disparities data. No finer-grained data are available. Of concern are the neighborhoods of St. Denis and Montreuil, which have significant French speaking West African immigrant populations. These neighborhoods are located in the northeast of Paris. We propose to supplement existing data to identify correlations between neighborhood and breast cancer mortality in the following manner: (1) with assistance from the directors of medical oncology at two hospitals (Avicenne, Tenon) that serve these neighborhoods, identify a sample of 200 West African women and 200 controls who have been diagnosed with breast cancer during the past three years; (2) invite these women by mail (letters from oncology services); and, (3) interview by telephone to determine other factors such as treatment history and length of time in Paris (plus any evidence of dual residence or significant time spent in the country of origin). We then will obtain pathology reports and treatment histories of women in the sample.