Molecular Spectroscopic Photoacoustic Imaging for Breast Lesion Characterization

乳腺癌是女性中第二致命的癌症，将夺走美国4万多人的生命 仅在2015年就有几个州。乳房X光检查是早期乳腺癌检测的一线成像技术，但 致密乳房组织的存在降低了其诊断的准确性。由于它的广泛可用性和 为了提高癌症的发现率，超声经常被作为乳房致密的女性的二线检查 组织。然而，超声会导致许多假阳性结果，不必要的活检会增加 相关的医疗保健费用。这项研究提案的目标是开发一种成像方法，使 准确、非侵入性地表征乳腺局灶性病变，使其成为临床可操作的(随访活检或 需要手术)和不可手术的病变。我们建议使用光谱光声(Spa)分子 成像结合了一种新的临床可翻译的造影剂，可以结合到当前的 临床超声成像工作流程。这种新的造影剂将通过将两种临床使用的药物相结合来开发 成分：首先，一种基于纤维连接蛋白的结合配体(FN3-支架)，其类似版本具有 已被证明对患者是安全的；第二，近红外荧光染料吲哚青绿(ICG)， 这是FDA批准用于患者静脉注射的药物。ICG-FN3-支架将针对最近确定的 和验证的乳腺癌标记物B7-H3，我们已经证明它在各种类型的乳腺癌中高度表达 将人类乳腺癌与正常乳腺组织和良性乳腺病变患者进行比较。会是 利用Flow合成、测试和优化其在小鼠和人细胞系中的B7-H3结合能力 细胞学。由于ICG可以基于其束缚状态T0在光学吸收光谱中经历显著移动 蛋白质，通过共聚焦显微镜的活细胞成像实验，我们将评估B7-H3受体 对比剂介导的内吞作用导致ICG在细胞内释放，并伴有连续的光谱漂移 它的吸收光谱。这一转变可以被用来区分成像信号与绑定和非绑定信号 结合造影剂，从而增加肿瘤对背景的信号。最后，测试B7-H3-靶向能力 SPA分子成像以区分临床可操作和不可操作的病变，转基因 采用小鼠乳腺癌模型(FVB/N TG(MMTV/PyMT634-1))。动物在不同的地方 年龄，对应于不同的组织病理疾病阶段(正常、增生、DCIS和乳房 癌症)，将在静脉注射B7-H3靶向ICG-FN3和SPA成像信号后进行SPA成像 将确定阈值，以区分良性病变和恶性病变。这之后将是一个 评估以B7-H3为靶点的SpA诊断准确性以鉴别临床可操作的前瞻性研究 在这个模型中，基于SpA成像信号的不可操作的病变。我们的研究将为 通过改进病灶的非侵入性特征，对当前临床乳腺成像实践进行了重大改变 乳房病变，有可能极大地改变乳腺癌患者的未来治疗。

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.