Internal chemical exposure study among Mexican immigrants
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Non-technical overview of the research topic and relevance to breast cancer: 
 
 Breast cancer risk increases with number of generations in the U.S. and with younger age at migration among U.S. Latinas. These observations strongly suggest that the changes in the environment and lifestyle associated with longer residence in the U.S. increase Latina women’s exposure to harmful factors and as a result increase their breast cancer risk. Previous studies have attempted to identify the factors that could explain the differences in breast cancer risk among Latina immigrants using measures of exposure obtained through questionnaires. However most of these studies lack insights into underlying biological mechanisms. It is known that people with similar reported exposures are not equally susceptible to disease, probably due to variation in the way substances produced within or outside our bodies are broken down and handled inside them. There is a need for new studies that objectively measure internal levels of exposure among U.S. immigrants. Our study will assess how the migratory experience influences the levels of potentially harmful substances present in the blood of Mexican American women and potentially increases their risk of developing breast cancer. 
 
 
 
 
 
 
 
 The question(s) or central hypotheses of the research: 
 
 We predict that women who have been exposed to the U.S. environment and lifestyle for longer and from a younger age, will have higher levels of potentially harmful substances in their blood. In this case, potentially harmful substances we are measuring are reactive electrophiles (substances attracted to electrons that damage DNA and proteins), and hormone receptor disruptors (chemicals that mimic the effect of estrogen or androgen on cell receptors). We also predict that particular types of reactive electrophiles and hormone receptor disruptors will be measured at different levels depending on duration of residence in the U.S. and age at migration and when comparing women with and without breast cancer. 
 
 
 
 
 
 
 
 The general methodology: 
 
 We will measure multiple chemical exposures that are detectable within the body of any given individual without targeting any one in particular. Our project proposes a shift from breast cancer candidate exposure analysis to an exposure-wide analysis. We plan to use mass- spectrometry (a substance separation procedure) and cell-based assays to measure reactive electrophiles and hormone receptor disruptors. We will evaluate the levels of these two substances among 90 Mexican American women who participated in the San Francisco Bay Area Breast Cancer Study (SFBCS). We will compare levels of 30 women born in the U.S., 30 born in Mexico who moved to the U.S. before puberty, and 30 who moved to the U.S. as adults. Each migration group will include equal numbers of pre- and post-menopausal women. Through linkage with the California Cancer Registry, we expect to identify approximately 30 women who developed breast cancer since they participated in the study. We will contrast the reactive electrophile levels and hormone receptor disruptor activity of these women who have developed breast cancer to those of women who have not yet developed the disease. 
 
 
 
 
 
 
 
 Innovative elements of the project: 
 
 The innovation in this proposal comes from the idea of combining information on migration history with untargeted measures of internal exposure to potentially harmful substances among Mexican Americans. By avoiding a priori assumptions about what specific chemicals are likely to affect breast cancer risk, we expect to open new avenues of research and discover new biological markers of risk (or biomarkers) as well as new modifiable risk factors that could be targeted through prevention programs to reduce breast cancer incidence among higher generation Latinas.