Flow chart of patient inclusion. Cases were centrally reviewed by a panel of LYSA and BC Cancer experts in hematopathology and medical oncology. Inclusion criteria for the GZL cases were based on World Health Organization classification; cases with a cHL-like morphology with strong and diffuse CD20 expression and other B-cell markers were also included (supplemental Methods). Cases with Epstein–Barr virus-encoded small RNAs (EBER) in situ hybridization positivity in >90% of tumor cells were diagnosed as poly-EBV-L. A total of 109 samples were collected, including 29 FFT biopsies submitted for laser microdissection (LMD) (“discovery cohort”) and 80 FFPE samples, of which 53 could be sequenced with a capture target panel of 217 genes (“extension cohort”). Eleven cases with coverage <100× were excluded to reduce false negative results related to low coverage.