Molecular Approaches to Diagnosis in Ewing Sarcoma: Targeted RNA Sequencing.

Molecular testing of pathognomonic gene fusions is mandatory for small round cell tumor diagnosis, including Ewing sarcoma which is indeed defined by a variety of chimeric genes. Reference laboratories are increasingly implementing NGS-based techniques to overcome several limitations of conventional singleplex determinations. We have been early adopters of a targeted-RNA sequencing method based on Anchored multiplex PCR, which allows assessing several fusion transcripts simultaneously with previous knowledge of only one partner gene. Here we describe in detail our protocol and tips for nucleic acid extraction, library preparation, sequencing, and reporting of gene fusions.