Environmental Chemical Body Burden and Prospective Breast Cancer Risk in the Cancer Prevention Study-3 Cohort

今天，有超过8.5万种在EPA注册的合成化学品，但只有10%进行了测试 动物研究中的致癌性。在接受检测的人中，约有200人显示出致癌和/或 乳腺肿瘤增多。然而，很少有化学物质在人体研究中得到评估，结果是 对人类的影响一直没有定论。我们的研究将集中在全氟烷基和多氟烷基的化学体内负荷 在绝经过渡期间发生浸润性乳腺癌的风险。 这些“永恒的化学物质”无处不在、经久不衰，并具有很高的公众利益，但对其可能性的研究 与乳腺癌的关系一直有限。我们假设，这些人的身体负担水平升高 内分泌干扰物(EDCs)会增加患浸润性乳腺癌的风险， DNA甲基化(DNaM)和乳房微环境的改变是将这些联系起来的机制 接触化学物质和乳腺癌。我们将使用三管齐下的方法来检验这一假设。具体而言 目标1，我们将对美国癌症协会癌症预防研究中的女性进行一项前瞻性研究 (CPS-3)评估绝经过渡期间全氟辛烷磺酸的身体负担与 随后发展为浸润性乳腺癌。我们将测量采集的血浆样本中的全氟辛烷磺酸水平 1000名CPS-3参与者和1000名匹配的无癌患者在浸润性乳腺癌诊断前1至7年 CPS-3参与者，抽血时年龄均在40岁至57岁之间。在具体目标2中，研究相同 参赛者，我们将使用InfiniumMegylationEPIC BeadChips测量dNaM，并进行表观基因组- 广泛关联研究(EWAS)以确定无癌人群中dNaM的变化与PFAS水平的关系 参与者。然后，我们将确定与PFAS相关的dNaM变化与 罹患乳腺癌。这些有价值的dNaM数据还可以在以后用于其他结果，包括 暴露于其他EDC。在具体目标3中，我们将确定全氟辛烷磺酸对组织和分子的直接影响。 基因组特征良好的原发人类中与癌症起始易感性相关的水平状态 乳腺上皮细胞(HMECs)。在原代乳腺细胞中识别这些机制至关重要。 这一点很重要，因为全氟辛烷磺酸的作用机制通常因组织而异。我们将使用2-D培养来确定 短期暴露和3-D培养的影响，以确定长期化学暴露对 上皮谱系的变化与加速衰老和基因组中与年龄相关的分子变化相一致 甲基化、谱系特异性转录和细胞角蛋白。这种多学科方法的结果 将促进我们对接触PFAS对患乳腺癌风险的影响的理解 重要的易感窗口。最终，我们希望我们提议的项目的结果将确定一个 环境暴露的综合生物学特征，提供对乳腺癌的机械性见解 来自EDC的发展，并为减少或减轻暴露的预防战略的未来研究提供信息。

Today there are more than 85,000 EPA-registered synthetic chemicals, but only 10% have been tested for carcinogenicity in animal studies. Of those tested, ~200 have shown evidence of causing cancer and/or an increase in mammary tumors. However, few of the chemicals have been evaluated in human studies, and results in humans have been inconclusive. Our study will focus on chemical body burden of per- and poly-fluoroalkyl substances (PFAS), and concomitant risk of developing invasive breast cancer during the menopausal transition. These “forever chemicals” are pervasive, enduring, and of high public interest, yet studies of their possible relationship to breast cancer have been limited. We hypothesize that elevated body-burden levels of these endocrine-disrupting chemicals (EDCs) will increase the risk of developing invasive breast cancer, and that alterations in DNA methylation (DNAm) and the breast microenvironment are mechanisms that link these chemical exposures and breast cancer. We will test this hypothesis using a three-pronged approach. In Specific Aim 1, we will conduct a prospective study of women in the American Cancer Society Cancer Prevention Study-3 (CPS-3) to assess the association between body burden of PFAS during the menopausal transition and subsequent development of invasive breast cancer. We will measure PFAS levels in plasma samples collected 1 to 7 years before invasive breast cancer diagnosis in 1000 CPS-3 participants and 1000 matched, cancer-free CPS-3 participants, all between 40 and 57 years of age at blood draw. In Specific Aim 2, studying the same participants, we will measure DNAm using Infinium MethylationEPIC BeadChips and conduct an epigenome- wide association study (EWAS) to identify DNAm changes associated with levels of PFAS in the cancer-free participants. We then will determine the association between the PFAS-associated DNAm changes and risk of developing breast cancer. This valuable DNAm data also can be used later for other outcomes, including exposure to other EDCs. In Specific Aim 3, we will determine the direct effects of PFAS on tissue- and molecular- level states associated with susceptibility to cancer initiation in genomically-well-characterized primary human breast mammary epithelial cells (HMECs). Identifying these mechanisms in primary breast cells is critically important, as PFAS mechanisms of action generally differ by tissue. We will use 2-D cultures to determine the effects of short-term exposures and 3-D cultures to define the effects of protracted chemical exposures on changes in epithelial lineage consistent with accelerated aging and age-related molecular changes in genome methylation, lineage-specific transcription, and cytokeratin proteins. Results from this multi-disciplinary approach will advance our understanding of the effects of PFAS exposures on risk of developing breast cancer during an important window of susceptibility. Ultimately, we hope results from our proposed project will identify an integrated biological signature of environmental exposure, deliver mechanistic insights into breast cancer development from EDCs, and inform future studies for prevention strategies to reduce or mitigate exposures.