imaging system quickly detects molecular marker in glioma brain, allows removal of the tumor -
During the surgery the tumor, surgeons work to remove the tissue of the tumor without damaging surrounding healthy tissue. This is particularly critical during the removal of the brain gliomas, such as damage to the surrounding healthy brain tissue can have significant effects on neuronal function of a patient. On the other hand, if the cancerous tissue is not completely eliminated, the tumor can regenerate. To answer these questions, researchers funded by NIBIB have developed an imaging system that quickly detects and accurately molecular marker found in gliomas of the brain. He promises to improve the accuracy of these difficult surgeries for complete removal of the tumor, while reducing residual damage to brain tissue and neuronal function.
The imaging system is known as the desorption ionization mass spectrometry by electrospray (DESI MS). The technique was developed by R. Graham Cooks, Ph.D., Purdue University and the study of the brain was done with collaborators at Harvard Medical School and Dana-Farber Cancer Institute, and is described in June 30 issue of the Proceedings of the national Academies of science. MS DESI promises to be a significant improvement over the current method of tumor tissue of the brain distinguish healthy tissue, which is based on an extremely long and difficult procedure for surgeons and patients.
The current protocol uses extemporaneous pathology, which involves removing the tissue suspected tumor and has been analyzed by pathologists. They use a process of freezing and staining which takes about 20 minutes and is too slow to be repeated several times during surgery. This method, developed there over 150 years, is both inefficient and lacks precision. This may result in incomplete removal of the tumor and regrowth, as well as damage to healthy tissue inadvertently, which can cause significant losses in the operation for patients.
The new technique solves some of the problems of the current method. Researchers use the ability of mass spectrometry to identify metabolites in brain tumors but not in healthy tissue. Surgery progresses, tissue samples are taken and sprayed a liquid loaded that is projected onto the fabric surface, raising of the droplets; The droplets are then sucked into a mass spectrometer, where the mass and charge of the metabolites are measured. Cerebral gliomas produce large amounts of a metabolite of the tumor, 2-hydroxyglutarate (2-HG) which is captured in the droplets. This rapid objective method allows a clear delineation of the tumor relative to non-tumor tissue, so surgeons can remove all and only the tumor tissue.
DESI MS system was first tested on samples of 35 glioma patients. Twenty-one of the 35 samples contained high levels of 2-HG, a product of the mutant form of a gene known as HDI , which is associated with tumor formation. The results clearly demonstrate that DESI MS can detect 2-HG in tumor tissue with a very high sensitivity and specificity.
The researchers continued to test the system in an operating room. The group has installed a complete system DESI MS in advanced multimodality guided by operating picture (AMIGO) suite at Brigham and Women's Hospital is part of the National Center for Image-Guided Therapy. The surgical suite AMIGO is an operating room with integrated imaging devices such as MRI, so that the surgeon may use to map the preoperative tumor. Tumor tissue sections from two patients were examined by DESI MS. In both cases, postoperative analysis confirmed that intraoperative DESI MS was specifically detected the presence of 2-HG in each tumor.
Researchers selected detection 2-HG to test DESI MS system because approximately 80% of gliomas and glioblastomas are associated with mutations in the gene HDI , which translates by high levels of 2-HG. The approach described here may be applicable to the tumor resection 2-HG-production.
Gliomas are tumors of glial brain cells and represent the majority of malignant brain tumors in adults. Gliomas represent approximately 30% of all tumors of the brain and central nervous system and 80% of all malignant brain tumors. These experiments provide proof of concept of precision and practicality of DESI MS system, and suggest that the system can be used with this common tumor 2-HG-production, and other tumors in which a metabolic marker malignancy occurred.
DESI MS system has been shown to be extremely accurate and was easily adapted for use in the clinical setting. He has no limitations of MRI, which can not provide information on the type of tumor, and requires surgery interrupted for an hour or more for scanning and interpreting the results. In addition, each operating room containing an MRI machine costs more than $ 10 million. However, DESI MS platforms could be implemented in any operating room to a very small fraction of the cost. The MS system DESI promises to be a powerful new tool for clinical and research applications with the potential to transform the surgical care of patients with brain tumors and other solid tumors.
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