The purpose of the Personal Environmental Risk Factor Study (PERFS) pilot project was to develop methodologies and a questionnaire for a future population-based case-control study to investigate the role of selected environmental exposures in breast cancer development. Identification of etiologically relevant exposures during a period of potential vulnerability proximate to disease onset offers the possibility of clinical disease prevention even when disease initiation may have already occurred many years earlier. Certain personal environmental agents or combinations of agents may influence disease promotion. Therefore, this pilot study focused on exposures that occurred during the ten-year period prior to diagnosis for cases and the last ten years for controls, rather than more historic exposures. For this pilot study, we used a community-based research approach. In our collaborative efforts, community members participated with academic researchers in all phases of the research, including research question identification, study design, development of research tools, development of the human subjects protocol, and report writing. Community member inclusion was based upon the concept that community participation could improve the relevance of scientific studies and ultimate success of the research by encouraging an ongoing dialogue between community members and academic representatives. Early activities of this project focused on the collection of input from the community regarding the possible role of environmental factors in the incidence of breast cancer in Marin County. The intent was to inform the scientists of community concerns, enhance the research team's understanding of the community being studied, and provide interested community members with a better understanding of the strengths and weaknesses of traditional research methods through active participation in the research process. This pilot study identified specific testable hypotheses through review of the literature and consultation with relevant experts and the affected community. Initially, the study was to focus on modifiable personal environmental exposures that are associated with breast tumor promotion and higher socioeconomic status (SES). However, little information was available in the scientific literature regarding the putative mechanism by which some of the suspected environmental factors may act (i.e., initiator vs. promoter). Likewise, little is known about the distribution of personal environmental risk factors by socioeconomic status. Therefore, tumor promotion involvement and association with SES were not very useful as selection criteria, and selection of topics was based primarily on published scientific findings of human studies and community input. This study was approved by the Institutional Review Boards at the University of California at San Francisco (Committee on Human Research) and at the University of California at Berkeley (Committee for the Protection of Human Subjects).