NSH Poster Podcast: P32 (2024)

The Use of Immunohistochemistry vs. qPCR to Detect BRAFV600E in Thyroid Cancer- Kannitha Chek HTL (ASCP), Nicholas Hoo-Fatt, MS, HTL (ASCP), DP, Samantha Diamond, M.D., Haresh Mani, M.D., Myong Ho “Lucy” Nam, M.D.

Introduction: This study aimed to validate the effectiveness of the Ventana anti-BRAFV600E antibody in detecting the BRAFV600E mutation in thyroid cancer using immunohistochemistry (IHC) as an initial screening test. The BRAFV600E mutation is a common genetic alteration in thyroid cancer, particularly papillary thyroid carcinoma (PTC), and detection is crucial for prognosis and treatment decisions. Methods: The research examined 12 thyroid cancer cases (11 PTC and 1 anaplastic thyroid carcinoma) and 12 non-cancerous thyroid cases. This study was conducted by using both the IHC BRAFV600E antibody as well as genetic testing methods including Next-Generation Sequencing (NGS) and the Biocartis Idylla rapid qPCR module for BRAF mutation. Results: The antibody successfully identified the BRAFV600E mutation in all cancer cases, aligning with results from other genetic testing methods, and as expected, non-cancerous cases showed no mutation-specific staining. The study highlighted important considerations in interpreting IHC results, such as the presence of non-specific brown staining due to colloid containing brown pigments in negative cases. It also emphasized the importance of proper tissue representation, as demonstrated by one case that initially lacked staining. While the research provides strong evidence for the accuracy of the Ventana anti-BRAFV600E antibody, it also identified limitations. The study lacked PTC cases negative for the BRAFV600E mutation, which would have provided a more comprehensive validation. Conclusion: The researchers suggest further investigation with a broader range of samples, including more anaplastic thyroid carcinoma cases and follicular variant of PTC, to explore potential correlations between tumor heterogeneity and staining intensity. This validation study contributes to improving thyroid cancer diagnosis and treatment by authenticating the reliability IHC methods in detecting a key genetic mutation. It also highlights the importance of continued research to optimize diagnostic methods in thyroid cancer.