Compositional and Functional Analysis of Breast Density in Human Tissue

乳房X光摄影是乳腺癌风险的有力预测指标。有辐射感受区的女性 覆盖超过50%的组织区域，患乳腺癌的风险比 只有很少或没有辐射感受区的女性。据估计，几乎三分之一的乳腺癌发病率是 这是由于调节乳房密度的生物变量(遗传和环境变量)造成的。鉴于此， 乳房密度与乳腺癌风险之间有很强的相关性，令人惊讶的是，人们对此知之甚少 关于致密乳房组织的特征或来源。 我们假设基质和上皮之间的分子相互作用代表了一些 乳房组织中发生的最早的变化，允许恶性转化，因此可能 可作为乳腺癌早期阶段的预测指标。我们认为，间质增多的特征 高密度乳腺摄影中细胞外基质(ECM)和分子标志物的重构 乳房代表着一种“激活”的基质。激活的间质(AS)类似于在 正常的、非病理的过程，如形态发生和伤口愈合，也可以在 结缔组织增生症等病理状态。而正常的间质-上皮相互作用积极抑制 癌前表型、激活的间质可以成为癌症进展的积极参与者。我们 假设高乳房密度和乳腺癌增加之间的机制联系 风险存在于导致乳房密度增加和 同时促进相邻上皮中启动细胞的恶性进展。这 提案将检查表型、分子和功能差异的几个方面 高、低密度乳腺组织中成纤维细胞和上皮细胞的分离 那些已经或没有患上乳腺癌的人。对这些组织的组织学和分子评估将 提供新的标记物，定义乳房密度增加和癌症风险增加。在项目2中，我们将 1)测定人乳腺组织的细胞和组织学组成 乳房X光摄影密度。与BioSig相关联的腺体的三维重建(3D) 数据库，将这些形态数据与分子数据相结合。(2)利用基因芯片，我们将 比较高密度和低密度(A)乳腺摄影组织的表达谱 和(B)来自在远处患上癌症的个人的匹配组织。这些标记物 可用于在项目3中通过免疫染色评估石蜡保存的良性乳腺活检组织 乳腺癌风险协会。在特定的目标3体内和体外重组实验将 提供对产生更高乳房密度和分子标记的细胞组合的洞察 与乳腺癌风险增加有关。(3)最终确定其功能表型。 从高密度和低密度的人乳腺组织中获得成纤维细胞。我们有 发现来自高钼靶密度组织的成纤维细胞保留了差异表达的 与生物相关的通路，如IGF轴。这些成纤维细胞已经被证明 当放置在小鼠重组模型中时，促进肿瘤进展。拟议的研究将 确定成纤维细胞增强致瘤表型的分子基础。

Mammographic breast density is a strong predictor of breast cancer risk. Women with radiodense areas covering greater than 50% of the tissue area have a 3 to 5 fold increase in risk for breast cancer compared with women with little or no radiodense area. It is estimated that almost 1/3 of breast cancer incidence is due to biological variables (both genetic and environmental) that modulate breast density. Given this strong correlation between breast density and risk for breast cancer, it is surprising that so little is known about the character or origin of dense breast tissue. We hypothesize that the molecular interactions between stroma and epithelium represent some of the very first changes that occur within breast tissue allowing malignant transformation and may therefore serve as a predictor of breast cancer in its earliest stages. We propose that features of increased stromal remodeling noted in the extracellular matrix (ECM) and molecular markers in mammographically dense breasts are indicative of an 'activated' stroma. Activated stroma (AS) is similar to stroma formed during normal, non-pathological processes such as morphogenesis and wound healing, and can also be found in pathological states such as desmoplasia. While normal stromal-epithelial interactions actively suppress preneoplastic phenotypes, activated stroma can become an active participant in cancer progression. We hypothesize that the mechanistic links between high breast density and increased breast cancer risk lie in the signal transduction pathways that lead to increased breast density and concomitantly promote malignant progression in initiated cells in the adjacent epithelium. This proposal will examine several aspects of the phenotypic, molecular and functional differences of mammary fibroblasts and epithelial cells isolated from individuals with high or low mammographic density that have or have not developed breast cancer. Histologic and molecular evaluation of these tissues will provide novel markers that define increased breast density and increased cancer risk. In Project 2, we will 1) Determine the cellular and histological composition of human breast tissues with high and low mammographic density. A three-dimensional reconstruction (3D) of the gland, linked to the BioSig database, will integrate this morphologic data with molecular data. (2) Using cDNA microarrays, we will compare expression profiles from tissues with high and low mammographic densities (a) to each other and (b) to matched tissues from individuals that have developed cancer at a distant site. These markers can be used in Project 3 to evaluate paraffin-preserved benign breast biopsy tissue by immunostains for association of risk for breast cancer. In Specific Aim 3 In vivo and in vitro recombinant experiments will provide insights into the cell combinations that generate increased breast density and molecular markers associated with increased breast cancer risk. (3) Finally we will determine the functional phenotype of fibroblast cells obtained from human breast tissues with high and low mammographic density. We have found that fibroblasts from tissue with high mammographic density retain differential expression of biologically relevant pathways such as the IGF-axis. These fibroblasts have been demonstrated to facilitate tumor progression when placed in a murine recombinant model. The proposed studies will determine the molecular basis for fibroblast enhancement of tumorigenic phenotypes.