Application Of Mass Spectrometry Imaging In Cancer Diagnosis

Our experiment adopts Air Flow Assisted Ionization mass spectrometry technology and imaging software technique to scan two kinds of common tumor tissues:breast cancer and thyroid tumor. Combined with bioinformatics method, we established the diagnostic pathology specimen method which depended on the lipid molecular. Moreover, we discussed the distribution features and significance of lipid molecules in tumor tissues and built up a lipid molecular database of every kinds of breast cancer and thyroid tumor. To implement the method of using lipid molecules to diagnose pathology specimens through carrying up visualization research with the imaging software, The study will provide theoretical basis and practical prove for IMS application in the field of clinical pathological diagnosis, and eventually to adapt IMS to difficult pathological cases and to make a reliable diagnosis. The significance of this study is to break through the clinical pathology bottleneck which relying on the morphology of cells and tissues, so that to diagnose cases at the molecular level by molecular imaging methods and the images clearly demonstrated the organization information. The research will establish the histopathology and Imaging Mass Spectrometry diagnosis system which are complemented each other, and will build a solid foundation for rapid and accurate clinical pathological diagnosis.In order to obtain significant and reliable statistically form the mass spectrum data, this study established a statistical model for data evaluation. In order to observe the distribution and relative abundance of these differences molecules in tissues in pictures form which is the most convenient and suitable for clinical diagnosis ways, we make a detail screen to molecular through Sore-plot, VIP list, independent sample t-test and visual imaging through imaging software. Moreover, we have identified a number of molecular structure by high resolution MS spectra and MS/MS to obtain the accurate mass spectrum analysis and combined with the lipid molecular fragmentation regularity and isotopic abundance ratio method, in addition to database search and literature search. Furthermore, we discussed the molecular biological significance. The research provides the theory bases and practice prove for mass spectrometry imaging technology application in clinical diagnosis. Our aim is to establish the histopathology and Imaging Mass Spectrometry diagnosis system which are complemented each other, and will build a solid foundation for rapid and accurate clinical pathological diagnosis. Eventually adapt IMS to difficult pathological cases and to make a reliable diagnosis. This has important significance for promoting the research and development of clinical pathological diagnosis.(1) Determine the key parameters of mass scan frozen sections and collecting tumors frozen specimens.First of all, we have collected more than100cases of breast tumors frozen specimens and80cases of thyroid tumors frozen specimens. Breast cancer frozen tissues included breast ductal invasive cancer and breast ductal carcinoma in situ, both these two kinds of tumor including high/medial/low grade tumors. Thyroid neoplasms frozen specimens included thyroid papillary carcinoma, follicular thyroid papillary carcinoma, thyroid follicular carcinoma and thyroid adenoma. Then, the key parameters of breast tumor and thyroid tumor mass scan frozen sections were determined, AFAI-MS was used for the mass spectrometric analysis of50cases of breast cancer and40cases of thyroid tumor specimens and obtained mass spectrometric data.(2) Mass spectrometry data preprocessing and statistical analysisThe AFAI-MS data of breast cancer and thyroid tumor tissue sections were reprocessing and convention these data into two dimensional data matrix and imaging each specimen using imaging software. In addition, selected the region of interest (ROI) form each specimen and extracted the mass data of ROI to form txt documents. Using Markerview software to combine groups data which need to compare, and then take multivariate statistical analysis use SIMCA-P software in the PCA and OPLS-DA model identification method. Moreover, data on breast cancer in each group include breast invasive ductal carcinoma and ductal carcinoma in situ, breast invasive ductal carcinoma high/medium/low differentiation, ductal carcinoma in situ high/medium/low level were studied; moreover, the papillary thyroid carcinoma/thyroid follicular variant of papillary carcinoma/thyroid follicular carcinoma, follicular carcinoma of the thyroid/thyroid adenoma/thyroid follicular variant of papillary carcinoma were studied too. Using extracted mass to charge ration (m/z) to imaging each specimen imaging and evaluate each sample mass spectrometry imaging map, comparing the imaging map and the corresponding pathological H&E in order to found the spatial characteristic of the these molecules and the law.(3) Identification lipid molecular structureIdentification these difference lipid molecular structure using high resolution MS spectra and MS/MS spectra, combined with the network database retrieval and review the literature to inference lipid molecular structure. Determine the species and specific catagories and to establish the breast cancer and thyroid tumor lipid database. Until now, we have identified29lipid molecules which can be differential diagnosis breast tumor classification and16lipid molecular which can be used for differential diagnosis breast tumor grade. According to the experimental results and review of the literature, to explore these lipid molecular biological significance and the related pathways with breast cancer and thyroid tumor development.(4) Adapt Imaging Mass Spectrometry to difficult pathological cases and to make a reliable diagnosis.According to the experimental results above, we adapted Imaging Mass Spectrometry to those difficult pathological cases and obtained mass spectrometry imaging. We combined the mass imaging and the corresponding H&E staining slice in order to obtain a reliable diagnosis results. Finally we will establish the histopathology and Imaging Mass Spectrometry diagnosis system which are complemented each other, and will build a solid foundation for rapid and accurate clinical pathological diagnosis.