Molecular Spectroscopic Photoacoustic Imaging for Breast Lesion Characterization

乳腺癌是女性第二大致命癌症，在美国将夺去4万多人的生命。 仅2015年一年。乳房X线摄影术是早期乳腺癌检测的第一线成像技术，但 致密乳腺组织的存在降低了其诊断准确性。由于其广泛的可用性和 提高癌症检出率，超声检查通常作为致密乳腺妇女的二线检查 组织.然而，超声导致许多假阳性结果，不必要的活检， 相关的医疗保健费用。这项研究计划的目标是开发一种成像方法， 准确、非侵入性地将乳腺局灶性病变定性为临床可操作的（随访活检或 需要手术）和不可操作的损伤。我们建议使用光谱光声（sPA）分子 成像与新的临床可转换的造影剂相结合， 临床超声成像工作流程。新的造影剂将通过结合两种临床使用的 组分：首先，基于人纤连蛋白的结合配体（FN 3-支架），其类似版本具有 已被证明在患者中是安全的;第二，近红外荧光染料，吲哚菁绿色（ICG）， FDA批准用于患者静脉注射ICG-FN 3-支架将靶向最近鉴定的 和经验证的乳腺癌标志物B7-H3，我们已经证明它在各种类型的乳腺癌中高度表达。 人类乳腺癌患者与正常乳腺组织和良性乳腺病变患者相比。将 在小鼠和人细胞系中使用流式细胞仪合成、测试和优化其B7-H3结合能力 细胞仪由于ICG可以基于其结合态在光学吸收光谱中经历显著的位移， 蛋白质，通过活细胞成像实验与共聚焦显微镜，我们将评估是否B7-H3受体 造影剂的介导的内吞作用导致ICG的细胞内释放，伴随连续的光谱移位 它的吸收光谱。这种偏移可以被用来区分成像信号与结合和非结合信号。 结合造影剂，从而增加肿瘤对背景信号的影响。最后，测试B7-H3靶向的能力 sPA分子成像，以区分临床上可采取行动和不可采取行动的病变，转基因 将使用乳腺癌发展的小鼠模型（FVB/NTg（MMTV/PyMT 634 Mul））。动物在不同 年龄，对应于不同的组织病理学疾病阶段（正常、增生、DCIS和乳腺癌） 在IV注射B7-H3靶向的ICG-FN 3和sPA成像信号后， 将确定阈值以区分良性病变与恶性病变。这将是一个 一项前瞻性研究，旨在评估B7-H3靶向sPA的诊断准确性，以区分临床可行性 基于该模型中的sPA成像信号从不可操作的病变中分离。我们的研究将为 通过改善病灶的非侵入性表征， 乳腺病变，有可能大大改变乳腺癌患者的未来管理。

Breast cancer is the second deadliest cancer in women, and will claim more than 40,000 lives in the United States in 2015 alone. Mammography is the first line imaging technique for early breast cancer detection, but the presence of dense breast tissue decreases its diagnostic accuracy. Due to its widespread availability and increased cancer detection rates, ultrasound is often performed as a second line test in women with dense breast tissue. However, ultrasound results in many false positive findings with unnecessary biopsies with increased associated health care costs. The goal of this research proposal is to develop an imaging approach that allows accurate, non-invasive characterization of focal breast lesions into clinically actionable (follow-up with biopsy or surgery is needed) and non-actionable lesions. We propose using spectroscopic photoacoustic (sPA) molecular imaging combined with a new clinically-translatable contrast agent that can be incorporated into the current clinical ultrasound imaging workflow. The new contrast agent will be developed by combining two clinically used components: First, a human fibronectin-based binding ligand (FN3-scaffolds), similar versions of which have been shown to be safe in patients; and second, the near-infrared fluorescent dye, indocyanine green (ICG), which is FDA approved for IV injection in patients. The ICG-FN3-scaffold will be targeted at a recently identified and validated breast cancer marker, B7-H3, which we have shown to be highly expressed in various types of human breast cancer compared to normal breast tissue and benign breast lesions in patients. It will be synthesized, tested, and optimized for its B7-H3 binding abilities in murine and human cell lines using flow cytometry. Since ICG can undergo significant shifts in optical absorption spectra based on its bound state to proteins, through live cell imaging experiments with confocal microscopy, we will assess whether B7-H3 receptor mediated endocytosis of the contrast agent results in intracellular release of ICG with consecutive spectral shift of its absorption spectrum. This shift could be leveraged to differentiate imaging signal from bound and non- bound contrast agent, thereby increasing tumor to background signal. Finally, to test the ability of B7-H3-targeted sPA molecular imaging to differentiate between clinically actionable and non-actionable lesions, a transgenic mouse model (FVB/N Tg(MMTV/PyMT634Mul) of breast cancer development will be used. Animals at varying ages, corresponding to different histopathological disease stages (normal, hyperplasia, DCIS, and breast cancer), will be imaged with sPA following IV injection of B7-H3-targeted ICG-FN3 and a sPA imaging signal threshold will be determined to allow differentiation of benign vs malignant lesions. This will be followed by a prospective study to assess the diagnostic accuracy of B7-H3-targeted sPA to differentiate clinically actionable from non-actionable lesions based on the sPA imaging signal in this model. Our study will lay the foundation for a significant change to current clinical breast imaging practice by improving non-invasive characterization of focal breast lesions, with the potential of substantially changing future management of breast cancer patients.