PAHs and puberty in girls at increased breast cancer risk
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: Studies have shown that events and exposures early in life may influence the risk of developing breast cancer in adulthood. Puberty is a time when the developing breast is sensitive to carcinogens. It is well known that girls start puberty earlier now than a few decades ago. It is not known whether exposure to environmental chemicals contributes to the earlier start of puberty. In this study we will examine the role of polycyclic aromatic hydrocarbons (PAHs). These chemicals are widespread air pollutants from automobile exhausts, cigarette smoke, wood burning, and commercial incinerators. PAHs are also found in foods charred by grilling or broiling. Some PAHs have carcinogenic effects and have been linked with breast cancer. Little is known about the impact of PAH exposures on pubertal development which is important to study because early breast development and early menses increase the risk of breast cancer. Research question(s) or central hypotheses: In an established cohort of California girls we will study whether girls with higher PAH exposures have earlier puberty, earlier first menses, and a slower tempo of pubertal development (that is, a longer time between start of breast development and first menses). We will also use a novel technique called optical spectroscopy to measure characteristics in the girls� breast tissue (i.e., water, lipid, and hemoglobin content, oxygen saturation). We will evaluate whether the composition of the breast is different in girls with high or low levels of PAH exposures. About half of the LEGACY girls have a family history of breast cancer. Therefore they have a higher risk of developing breast cancer than girls without a family history. We will study whether the impact of PAH exposures on the age at puberty and first menses and breast composition is different in girls with a breast cancer family history compared with girls without a family history. General methodology: The setting of our study is the California site of the LEGACY Girls Study that enrolled girls ages 6-13 years. The girls had follow-up visits every 6 months, and we collected urine and blood samples, interview data, and measurements of height and weight. Since not all girls have started puberty or menses, we will continue to follow the girls so that we can learn when these pubertal events happen. Now that all girls are 10 years or older, all of them will be invited to participate in the measurement of breast tissue characteristics. We will perform laboratory analyses to measure PAH exposures in urine and blood samples. We will perform statistical analyses to evaluate whether girls with higher levels of PAH exposures have earlier puberty, earlier menses, a slower tempo of pubertal development, and different characteristics in their breast tissue. Innovative elements: Our study has several innovative elements. 1) We will study the pubertal development in two groups of girls: half with a family history of breast cancer and half without a family history. It has not been studied whether the influence of PAH exposure on the timing of puberty and menses differs in the two groups of girls. 2) We will use optical spectroscopy, a novel non-invasive technique, to measure characteristics in the girls� breast tissue. It is not known whether PAH exposures affect the breast composition in young girls. 3) We will measure biomarkers in the urine and blood samples to get good estimates of PAH exposure. Advocacy involvement and relevance to the human issues associated with breast cancer: We will partner with Ms. Catherine Thomsen from Zero Breast Cancer (ZBC) as our community advocate. Ms. Thomsen will advise us throughout the study on how to keep the girls interested in the study and on the content of newsletter that we share with participating families. She will help us developing reports and messages about our study findings that are useful to the LEGACY families. She will also work with us in the dissemination of study findings to community organizations, breast cancer and environmental advocates, and policy makers. Our findings will be important for the development and implementation of policies aimed at reducing exposure to environmental chemicals, such as PAHs.