Abstract：
With recent advances in cancer therapeutics, there is a great need for improved imaging methods for characterizing cancer onset and progression in a quantitative and actionable way. Collagen, the most abundant extracellular matrix protein in the tumor microenvironment (and the body in general), plays a multifaceted role, both hindering and promoting cancer invasion and progression. Collagen deposition can defend the tumor with immunosuppressive effects, while aligned collagen fiber structures can enable tumor cell migration, aiding invasion and metastasis. Given the complex role of collagen fiber organization and topology, imaging has been a tool of choice to characterize these changes on multiple spatial scales, from the organ and tumor scale to cellular and subcellular level. Macroscale density already aids in the detection and diagnosis of solid cancers, but progress is being made to integrate finer microscale features into the process. Here we review imaging modalities ranging from optical methods of second harmonic generation (SHG), polarized light microscopy (PLM), and optical coherence tomography (OCT) to the medical imaging approaches of ultrasound and magnetic resonance imaging (MRI). These methods have enabled scientists and clinicians to better understand the impact collagen structure has on the tumor environment, at both the bulk scale (density) and microscale (fibrillar structure) levels. We focus on imaging methods with the potential to both examine the collagen structure in as natural a state as possible and still be clinically amenable, with an emphasis on label-free strategies, exploiting intrinsic optical properties of collagen fibers.
摘要：
随着癌症治疗的最新进展，非常需要用于以定量和可行的方式表征癌症发作和进展的改进的成像方法。胶原蛋白,肿瘤微环境（和一般人体）中最丰富的细胞外基质蛋白，扮演着多方面的角色，阻碍和促进癌症的侵袭和进展。胶原蛋白沉积可以保护肿瘤具有免疫抑制作用，虽然对齐的胶原纤维结构可以使肿瘤细胞迁移，协助侵袭和转移。鉴于胶原纤维组织和拓扑结构的复杂作用，成像一直是在多个空间尺度上表征这些变化的首选工具，从器官和肿瘤规模到细胞和亚细胞水平。宏观密度已经有助于实体癌的检测和诊断，但是在将更精细的微观特征集成到该过程中方面正在取得进展。在这里，我们回顾成像模式，从二次谐波产生（SHG）的光学方法，偏振光显微镜（PLM），和光学相干断层扫描（OCT）到超声和磁共振成像（MRI）的医学成像方法。这些方法使科学家和临床医生能够更好地了解胶原蛋白结构对肿瘤环境的影响。在整体规模（密度）和微观规模（纤维结构）水平。我们专注于成像方法，有可能在尽可能自然的状态下检查胶原蛋白结构，并且仍然可以在临床上适应。强调无标签策略，利用胶原纤维的固有光学特性。
