The transformed HSs showed partial retention of their prior B-cell lymphomas' signatures, including expression of OCT2 in both cases and expression of BCL6 and enhanced expression of BCL2 in case 2.
Notably, all IGH/IGK-positive H/DC sarcomas were negative for B-cell-associated transcription factors PAX5 and BOB.1, whereas 4 of 7 IGH/IGK-positive histiocytic sarcoma cases were positive for Oct2.