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Exclusive interview / Dr. Anton Titov MD and Professor Dr. Sebastian Brandner, expert in molecular and genetic brain tumor diagnosis and neurodegeneration.
Let's start with brain tumors. When brain tumors are diagnosed clinically, neurosurgeons usually remove the tumor. And then the material from the tumor or from brain tumor biopsy, if it's done separately, ends up in your hands. Could you please walk us through, how do you diagnose brain tumors? How do you establish brain tumor molecular diagnosis? OK, so the neurosurgeon, as you correctly said, they send us the material and everything else they expect us to solve for them. And not only for them, but also for the oncologists, the neurologists, and, of course, for the patient. After we receive the tumor sample material, it is being fixed in a fixative, for just an overnight cycle, and this tumor material is processed into something that we can cut into very thin slices. So that results in the slides like this, it's a small glass slide, you can see here, and then the specimens are "mounted" in the center of the slide, and it goes to another procedure, where we dye the cells with a dye, so the nuclei, the cytoplasm, the [neuron] processes look distinctive under the microscope. After that, the actual diagnostic procedure starts. So we look through the microscope first - to identify what type of brain tumor it is. Is it intrinsic brain humor? or is it extrinsic brain tumor? Such as meningioma or metastasis... Or is it something entirely different? Is it inflammation? Sometimes we get material from the spine, which is actually not a brain tumor as such, which we then have to send to other specialists, because it's often soft tissue tumors. Now, back to the brain tumors. Under the microscope we make the first decision. The first decision is - what type of brain tumor is it? And that clearly defines and determines what we do next. We then order a number of stains that tell us a little bit more about the nature of the tumor. So we already know, for example, is this glioma? But we want to know a little bit more details: what type of glioma is it? What subtype? And so we order the second round of special stains. Nowadays it is all done on a machine, these special stains are called immunohistochemistry or immunohistochemical staining. A day later they arrive again on our microscope desk. We discuss them, we will look at them, That gives us a fairly clear idea what we are dealing with. And I would say, the very first step
- just looking at the stained slide - that we do with all the biopsies. And probably, in our hands, 60 - 70% of those biopsies require the second step, the immunostaining, particularly intrinsic brain tumors, gliomas, also many other types of tumors. After that we have a very good idea about nearly all brain tumors. But probably 10% of tumors, especially gliomas, they require additional tests. So we look further, because you want to trim down, we want to really go into detail. So that is the last step, it's called "molecular diagnostics". So this is done entirely differently. That leaves the domain of pathology and goes into molecular biology. So what we do there is that tissues are taken off from the blocks, off the slides, and is then prepared in a way so we can extract the nucleic acids, the DNA, and this material is then subjected to molecular pathology tests, usually quantitative PCR, and in rare cases, also to DNA microarray type of investigations. So this last step is probably done in 1% of the tumors, when all the other tests are not giving us sufficient clarity or sufficient details of information . All that information is then put into a report, This report is typed up on a computer, and the computer is connected to database. The database is then feeding back that information to the clinical teams. The moment we authorize the report electronically [to be released], it goes straight away to the hospital's clinicians, who can review that. But that's not the end of the diagnostic process.
How brain tumor is diagnosed by neuropathologist? Part 1 (2) top doctors washingtonian | |
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| Science & Technology | Upload TimePublished on 22 Jun 2018 |
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