ESH ALL 2021 | Diagnostic testing modalities for Ph-like ALL

Sarah Tasian, MD, The Children’s Hospital of Philadelphia, Philadelphia, PA, gives an overview of some of the diagnostic challenges for Philadelphia-like (Ph-like) acute lymphoblastic leukemia (ALL). It is known that most of the fusions seen in Ph-like ALL are cytogenetically cryptic and, therefore, can be missed on conventional testing. Optimization of fluorescence in situ hybridization (FISH) probes and flow cytometry to detect the TSLP receptor has improved the identification of Ph-like ALL patients. RNA-based fusion platforms to identify the specific kinase fusion involved are probably the most helpful test modality currently available, but it is somewhat more time-consuming than other diagnostic strategies. In pediatrics, low-density microarray can help identify patients who have a kinase-activated gene expression profile consistent with Ph-like ALL and identify Ph-positive disease. Dr Tasian emphasizes that it is a screening test and probably not necessary for adult patients. This interview took place during the 2021 European School of Hematology (ESH) 2nd Translational Research Conference on Acute Lymphoblastic Leukemia.