USE OF DIGITAL PATHOLOGY SIGNIFICANTLY IMPROVES THE QUALITY OF TISSUE MICROARRAY CONSTRUCTION
Prashant Bavi is a research pathologist at Research Centre, King Faisal Specialist Hospital, Riyadh, Saudi Arabia. He has a successful track record of over 50 publications in high impact peer reviewed journals and more than 70 presentations in international meetings. With 12 years of experience, he is well versed in oncology, biobanking, digital pathology, translational research & lab administration. Over the years, he has developed a diverse set of skills in anatomical pathology, molecular pathology, data management & biomarker validation. Other areas of his competence are scientific writing including reviewing manuscripts & serving on the editorial board. An avid proponent of digital pathology, he firmly believes in inculcating principles of productivity & time management such lateral thinking, mind mapping & “Getting Things Done” in research & diagnostic pathology. His long-term goals are harvesting the best quality samples, participate in meaningful biomarker discovery & making an impact on personalized medicine.
Background: In the last decade, tissue microarray(TMA) has been established in translational cancer research as a high throughput tool. Similar to digital pathology, traditional purists took time to adopt TMAs as a tool in biomarker discovery and validation; teaching and as a IHC control for validation. Technology transfer, setting aside funds to purchase an arrayer, and dedicated personnel to map slides and construct TMA are still major bottle necks. Final quality of a constructed TMA depends on the yield of slides and the number of representative cores arrayed. Study of rare events in pathology pose a particular challenge for the lab personnel to accurately identify the area of interest by superimposing the slide on the paraffin block before extracting the tissue core. Therefore, we studied the effect of digital pathology in mapping the region of interest and constructing TMA’s.
Methods: We constructed two identical TMA blocs of 0.6mm diameter from 50 rare histological events that included R&S cells from Hodgkin’s lymphoma, multifocal microscopic carcinoma in thyroid and lymphovasuclar embol/perineural infiltration in colorectal carcinoma. One array block was done in the traditional way and the other array we did digital mapping of scanned images from slides, printing the life-sized images. Slides were scanned with Aperio ScanscopeCS; mapping done with Imagescope and TMA constructed using Semiautomated Arrayer, CM1 Mirlacher, Neuenburg, Germany. Using a image manipulation program IrfanView, we printed the images in the same aspect ratio as it was scanned on a semi-transparent paper.
Results: Preliminary results of 10 microscopic multifocal papillary thyroid carcinoma showed a 100% accuracy in picking up the microscopic lesions as compared to 60% with the traditional approach. Remarkably accuracy was associated with a increase in speed.
Conclusions: Modifying the process of TMA construction by embracing digital pathology is beneficial and should be adopted routinely. The tangible benefits are:(i) improved accuracy; (ii) saves time (iii) increases the speed; (iv) potentially reduces errors of misidentification and (v) frees up the lab technician to be utilized for other tasks.
Although tissue microarray technology, as a high throughput tool, has revolutionized biomarker discovery in translational research, it has some key bottlenecks. Digital pathology has been used in IHC quantification. However, there is a potential of using scanned images for constructing tissue microarrays Embracing of these 2 technologies has immediate tangible benefits of improvement in speed, accuracy, saving of time and freeing up scarce technical staff. In addition this methodology reduced risk of misidentification and provides robust documentation of mapped images on for future usage.