An unsupervised MVA method to compare specific regions in human breast tumor tissue samples using ToF-SIMS.
An unsupervised MVA method to compare specific regions in human breast tumor tissue samples using ToF-SIMS.
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DOI：
10.1039/c5an02406d
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发表时间：
2016-03-21
期刊：
影响因子：
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通讯作者：
Gamble LJ
中科院分区：
文献类型：
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作者：
Bluestein BM;Morrish F;Graham DJ;Guenthoer J;Hockenbery D;Porter PL;Gamble LJ
使用成像飞行时间二次离子质谱（ToF-SIMS）和主成分分析（PCA）研究两组化疗前和化疗后的人乳腺肿瘤组织切片，以表征与肿瘤代谢灵活性和治疗反应相关的脂质。ToF-SIMS的微米空间分辨率成像能力提供了一种强大的方法，可以从传统成像技术无法获得的癌组织中获得空间分辨的分子和细胞数据。三个CA。通过将200 μm × 200 μm光栅区域扫描拼接在一起，对每个组织切片的1 mm 2区域进行分析。提出了一种利用ToF-SIMS图像的主成分分析来分离和分析感兴趣的特定组织区域的方法，该方法允许将细胞化区域与基质区域分离。然后将这些PCA生成的感兴趣区域用作掩模，以从特定的基质或细胞区域重建代表性光谱。与分析所有组织区域或分析病理学家突出显示的区域相比，这种无监督选择方法的优点是减少了光谱PCA结果中的分散。利用这种方法，化疗前与化疗后进行的乳腺组织活检的基质和细胞区域证明了使用带负电荷的离子物质的化学分离。在该样品组中，细胞区域主要是所有癌细胞。脂肪酸（即棕榈酸、油酸和硬脂酸）、单酰基甘油、二酰基甘油和维生素E谱在治疗前和治疗后组织之间存在明显差异。这些结果验证了一种新的无监督方法，可以使用成像ToF-SIMS数据来分离和解释癌症组织中的生物化学不同区域。此外，这里开发的方法可以提供一个框架，使用成像ToF-SIMS来比较各种组织样本，特别是在存在切片间差异的情况下，这使得难以使用连续苏木精和伊红（H&E）染色切片来指导西姆斯分析。
Imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS) and principal component analysis (PCA) were used to investigate two sets of pre- and post-chemotherapy human breast tumor tissue sections to characterize lipids associated with tumor metabolic flexibility and response to treatment. The micron spatial resolution imaging capability of ToF-SIMS provides a powerful approach to attain spatially-resolved molecular and cellular data from cancerous tissues not available with conventional imaging techniques. Three ca. 1 mm2 areas per tissue section were analyzed by stitching together 200 μm × 200 μm raster area scans. A method to isolate and analyze specific tissue regions of interest by utilizing PCA of ToF-SIMS images is presented, which allowed separation of cellularized areas from stromal areas. These PCA-generated regions of interest were then used as masks to reconstruct representative spectra from specifically stromal or cellular regions. The advantage of this unsupervised selection method is a reduction in scatter in the spectral PCA results when compared to analyzing all tissue areas or analyzing areas highlighted by a pathologist. Utilizing this method, stromal and cellular regions of breast tissue biopsies taken pre- versus post-chemotherapy demonstrate chemical separation using negatively-charged ion species. In this sample set, the cellular regions were predominantly all cancer cells. Fatty acids (i.e. palmitic, oleic, and stearic), monoacylglycerols, diacylglycerols and vitamin E profiles were distinctively different between the pre- and post-therapy tissues. These results validate a new unsupervised method to isolate and interpret biochemically distinct regions in cancer tissues using imaging ToF-SIMS data. In addition, the method developed here can provide a framework to compare a variety of tissue samples using imaging ToF-SIMS, especially where there is section-to-section variability that makes it difficult to use a serial hematoxylin and eosin (H&E) stained section to direct the SIMS analysis.