MSACL 2018 US Abstract

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Topic: Tissue Imaging & Analysis

Advanced Development of the MasSpec Pen for Cancer Diagnosis and Surgical Margin Evaluation

Livia S. Eberlin (Presenter)
University of Texas at Austin

Authorship: Jialing Zhang1, Marta Sans1, John Lin1, Noah Giese1, Nitesh Katta2, Wendong Yu3, Chandandeep Nagi3, James Suliburk4, Jinsong Liu5, Alena Bensussan1, Rachel J. DeHoog1, Kyana Y. Garza1, Anna G. Sorace6, Anum Syed6, Thomas Milner2, and Livia S. Eberlin1
1 Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712 2 Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712 3 Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030 4 Department of Surgery, Baylor College of Medicine, Houston, TX, 77030 5 Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030 6 Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX, 78712

Short Abstract

We have recently reported the development of the MasSpec Pen for rapid diagnosis of human cancer tissues. Here, new describe recent results on independent samples sets analyzed ex vivo, including new tissue types and improvements in cancer prediction. Suitability for in vivo analysis was further demonstrated by evaluating normal, cancer and margin tissue from mouse models during surgery. A laparoscopic version of the MasSpec Pen was designed and developed for minimally invasive procedures, and tested on fresh tissue samples. Our results demonstrate current efforts towards the translation of the MasSpec Pen into clinical workflows for rapid cancer tissue diagnosis.

Long Abstract


Accurate assessment of tissue margins during surgical oncologic procedures is essential to ensure complete tumor excision. Current methods for margin evaluation involve the examination of tissue sections by trained pathologists both intraoperatively and most often postoperatively. These approaches are both labor and time intensive, delaying the diagnosis and requiring the patient to come back for a second procedure in the case of a positive margin (1-6). Ambient ionization mass spectrometry (MS) has shown exceptional potential for rapid molecular diagnosis of cancer tissues, but few approaches have demonstrated their application for fresh tissue and in vivo analyses (7,8). We have recently developed an automated and biocompatible handheld device, the MasSpec Pen, for direct, real-time non-destructive sampling and molecular diagnosis of tissues (9). The MasSpec Pen was applied for ex vivo molecular evaluation of 253 human tissue samples, providing high sensitivity and selectivity for cancer detection (>96%). Here, we describe recent developments of this work for in vivo and ex vivo cancer tissue diagnosis and the design of a laparoscopic version of the MasSpec Pen for minimally invasive surgeries. New samples independent to our statistical model were analyzed in order to test and improve the predictive accuracy of our classifiers. Moreover, statistical models characteristic of human organs and malignancies, as well as different histological subtypes not previously investigated with the MasSpec were included in this study.


Human tissue samples from 276 patients including normal and cancer breast, ovarian, brain, pancreatic, lymph node; parathyroid and endometriosis tissues obtained from the Cooperative Human Tissue Network (CHTN), Asterand Biosciences (Detroit, MI), the Baylor College of Medicine Tissue Bank, and from prospective collections at the Seton Medical Center (Austin, TX). Pathologic diagnosis was used as the reference for our molecular database. In vivo experiments were performed during surgical resection of tumors using murine animal models. For classification, we applied the Lasso method using the glmnet package in the CRAN R language library (10). New samples were evaluated as an independent validation set for the previously published classifier (9). Performance was measured by sensitivity, specificity, accuracy, and AUC. The laparoscopic MasSpec Pec was made by crafting polytetrafluoroethylene (PTFE) conduits inside a larger tubing, and applying a thin sliver of silicone tubing at the terminal.


The MasSpec Pen is an automated and biocompatible handheld sampling probe that allows gentle, time- and volume-controlled extraction of molecules from a tissue sample using a discrete water droplet. The system contains three conduits for (1) water transport, (2) gas transport, and for (3) sample transport to the mass spectrometer. The entire process from sampling (3 s for extraction time) to mass spectral acquisition is completed in 10 s or less and is fully automated (9). Using the MasSpec Pen, we have analyzed a total of 276 new samples, including 37 brain samples (normal, meningiomas and glioblastomas), 60 breast samples as well as 20 metastatic breast in the lymph node and 17 normal lymph nodes, 40 ovarian samples (high-grade, low-grade and normal), 45 pancreatic samples (cancer and normal), 9 parathyroid cancer and 18 endometriosis tissue. The samples were analyzed ex vivo using water as the solvent system and rich molecular information, such as metabolites, fatty acids, sphingolipids (SP), glycerolipids (GL), and various classes of glycerophospholipids (GP), including doubly charged cardiolipins (CL), were observed in the negative ion mode. Similarities between the species detected and their relative abundances were observed between the MasSpec Pen and previously obtained DESI spectra (11, 12). Current efforts are being dedicated towards statistical analysis and evaluation of the results. We have further tested the MasSpec Pen for in vivo evaluation of muscle, tumor and margin tissue using murine models of human breast cancer. Differences in species detected as well as their relative abundance in the mass spectra were observed between the three tested regions both in vivo and ex vivo.

The Laparoscopic MasSpec Pen was designed and developed for laparoscopic and robotic surgeries. The device was tested on fresh mouse brain tissue, and comparable performance, in regards to analysis time and similarities in the mass spectra, was observed between the laparoscopic version and the handheld probe. Different size tips and tubing lengths were evaluated for performance and reproducibility.

Conclusions & Discussion

We have applied the MasSpec Pen for ex vivo cancer prediction of 276 patient samples independent to our previously reported database. We have expanded our classifiers to new tissue types and histological subtypes. In vivo analysis in murine models of breast cancer demonstrated successful and non-destructive molecular evaluation of tumor, margin and normal tissue. We anticipate that the validation of the statistical models, as well as the application of the MasSpec Pen towards the diagnosis of new human cancers will further demonstrate its capabilities for rapid ex vivo and in vivo cancer diagnosis of tissue samples. The development of the Laparoscopic MasSpec Pen offers an exciting opportunity to incorporate our device into surgical systems for minimally invasive procedures.

References & Acknowledgements:

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5. T. A. Buchholz et al., Margins for Breast-Conserving Surgery With Whole-Breast Irradiation in Stage I and II Invasive Breast Cancer: American Society of Clinical Oncology Endorsement of the Society of Surgical Oncology/American Society for Radiation Oncology Consensus Guideline. Journal of Clinical Oncology 32, 1502-+ (2014).

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8. J. Zhang, W. Yu, J. W. Suliburk, L. S. Eberlin, Will ambient ionization mass spectrometry become an integral technology in the operating room of the future? . Clinical Chemistry in press, (2016).

9. J.Zhang, et al., Nondestructive tissue analysis for ex vivo and in vivo cancer diagnosis using a handheld mass spectrometry system. Science Translational Medicine 9, eeana 3968 (2017)

10. R. Tibshirani, Regression shrinkage and selection via the Lasso. Journal of the Royal Statistical Society Series B-Methodological 58, 267-288 (1996).

11. M. Sans, K. Gharpure, R. Tibshirani, J. Zhang, L. Liang, J. Liu, J. H. Young, R. L. Dood,
A. K. Sood, L. S. Eberlin, Metabolic markers and statistical prediction of serous ovarian cancer aggressiveness by ambient ionization mass spectrometry imaging. Cancer Res. 77, 2903–2913 (2017). 

12. L.S. Eberlin, et al. Ambient mass spectrometry for the intraoperative molecular diagnosis of human brain tumors. PNAS. 110, 1611-1616

Financial Disclosure

Board MembernoAnalytical Chemistry Journal, ASMS Diversity Committee

IP Royalty: no

Planning to mention or discuss specific products or technology of the company(ies) listed above: