Dr. Theresa Brown

Cell Isolation and FISH Testing in a Cytogenetics Lab

Dr. Theresa Brown, Director of Cytogenetics, Tulane University
Dr. Theresa Brown

Dr. Theresa Brown is an Associate Professor and the Director of the Cytogenetics Lab at Tulane University. In this interview, Dr. Brown shares information about how they perform cell isolation and fluorescence in-situ hybridization (FISH) testing in their lab.

This interview was conducted in collaboration with Oxford Gene Technology.

Theresa’s Story: Pursuing a Passion in Genetics

What inspired you to pursue a career in cytogenetics?

I knew in highschool that I wanted to pursue a career in genetics, so I did my undergraduate degree at Purdue University. Afterwards, I wanted to pursue my passion for human genetics, so I obtained my first job in a cytogenetics lab. From there, I went on to graduate school and received my PhD in medical genetics at the University of Alabama, where I studied both cytogenetics and medical genetics. Since then, I have been passionate about the topic of cytogenetics.

Can you tell us about your current role?

My first job after graduate school was in a large cytogenetics reference lab. From there, I moved to the southeast region to help grow a lab while also supporting others in starting new labs. I have been at Tulane University now for 5 years, running a smaller academic lab. We do a little bit of everything, but mainly perform hematology and oncology testing.

The Ins and Outs of a Cytogenetics Lab

Can you tell us more about what your lab does?

99% of our work is hematology/oncology testing. We receive specimens from patients with either myeloid disorders or multiple myeloma, many of whom get an autologous or allogeneic stem cell transplant. The majority of our work is focused on FISH and chromosome analysis on cancer specimens.

Could you give a high-level description of what assay development looks like in your lab?

We don’t do much validation chromosome-wise, since it has been around for so long. However, we are constantly doing quality checks and adding on new probes to our FISH panels to help improve patient care. Quality is very important to us and I follow the College of American Pathologists (CAP) guidelines while also trying to improve our current methods.

What does your bone marrow preparation step currently involve?

As soon as we get the fresh specimen in the lab, we take 1 mL of the sample and go immediately to the cell isolation step. We use the rest of the sample to set up an unstimulated and a mitogen-stimulated cell culture that grows for 96 hours. While this cell culture step takes time, we find that it is needed to ensure we have the right cells for determining correct abnormality rates.

Are there any specific FISH panels that you test for?

The vast majority of our panels are for multiple myeloma and myelodysplastic syndromes. We also get some panels for acute myeloid leukemia and chronic lymphocytic leukemia.

How important is cell purity and viability for cytogenetic assay development?

Both are very important, especially in multiple myeloma. Plasma cells don’t like to divide in culture, they’re low in number, and they start dying as soon as we take a tap from the patient. We realized early on that we need those very specific cells that express CD138. Isolating these cells has greatly improved the abnormality rates and our confidence in the fact that we are giving an accurate answer to accompany the pathology result to the clinician.

CD138 Cell Isolation for Sharper FISH Results

Why did you decide to start using EasySep™ for CD138 cell isolation?

When I was in Southern California, the core research lab there was using EasySep™ while the clinical diagnostic lab was using a stain to identify cells. It was a very laborious, three day process, so we decided to take EasySep™ into the clinical lab. We found EasySep™ to be much better than what we had used in the past, and RoboSep™ automated the process, which was very helpful.

Later on when I came to Tulane University, they were using a different, more time-consuming method and I wasn’t very happy with the results. We brought in EasySep™ and found it to be much more simple and easy, and the results were better than what we had previously seen from the flow cytometry results.

After implementing CD138 cell separation, how did it improve FISH results?

When I first started doing isolation, I was getting a lot of diffuse signals because the cells tend to stick together. When I switched over to EasySep™, I didn’t have that problem anymore—the cells would spread better and appear more flat. There was also a reduction in the background signal, and I was able to get very clean, bright, and sharp FISH results with EasySep™.

Automated CD138 Cell Isolation

What made you choose an automated separation with RoboSep™-S instead of manual?

We had a high volume of samples coming into our lab. Manual isolation is a 2 - 3 hour process, and we didn’t have enough hands in the lab. When we got the RoboSep™-S instrument, that was a major help for us. We could just load the samples in, walk away to perform other tasks such as analysis, and then go back to collect the isolated cells. The next day we’d just get the pellet, perform a full FISH panel, and get our results.

What did the validation process look like for RoboSep™-S?

We compared FISH results from 5 - 10 samples where we had performed either manual extraction or CD138 cell isolation with RoboSep™-S. We found that the FISH results were better on RoboSep™-S. With automated cell isolation, we tend to get a larger pellet size, enabling us to do a full multiple myeloma panel (6 probes). With the manual isolation, we’re not always able to do a whole panel.

Did you track abnormality rates before and after implementing RoboSep™-S CD138 cell isolation? If so, how did they change?

We track abnormality rates on a monthly basis. My overall abnormality rate went from around 30% prior to implementing CD138 cell isolation to 40-50% after implementing RoboSep™-S into our workflow. It makes me happy to know that we’ve found the abnormalities and we’re giving good results to the clinician.

Was it easy to incorporate RoboSep™-S into your workflow?

Yes! RoboSep™-S came in at the very beginning of COVID. However, we were able to get the support we needed from STEMCELL through virtual training that enabled us to set up the instrument and get it going.

Final Remarks

Do you have any tips for other labs who want to incorporate RoboSep™-S into their workflow?

We were lucky because I was previously in a lab that had used RoboSep™-S, so I was able to take that protocol from my previous lab and use it in the new lab. I’m always happy to help other labs as well and share protocols with them, because we don’t need to be re-inventing the wheel.

It is a very good investment if you have the volume of work in your lab. It is easy to incorporate and well worth the money as it can help free up technicians who can instead spend that time on performing analysis, which is the most important step.

What is your overall experience using CytoCell FISH probes with the RoboSep™-isolated CD138+ cells?

It's been a perfect marriage! Both RoboSep™-S and Cytocell probes are very straightforward and easy to use, and have enabled me to get consistent results.

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*EasySep™ and RoboSep™ are for research use only and were validated by the researcher based on the respective regional guidelines for their specific application.

Learn More About CD138 Cell Isolation

How Does EasySep™ Work?

Learn about the technology behind EasySep™, which can be used to isolate highly purified CD138+ plasma cells for downstream FISH analysis.

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How Does RoboSep™ Work?

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Try RoboSep™ in Your Own Lab

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