This statement is not consistent with the citation or is phrased in a way that is difficult to parse.
"These tumours overwhelmingly show concurrent MYC and BCL6 translocations, and the existence of activated B-cell-like high grade B cell lymphoma with BCL2 translocation is controversial[2]"
Perhaps I don't follow the narrative properly. Which tumours is "these" meant to refer to? The HGBL DH/TH overall actually overwhelmingly have concurrent BCL2/MYC (not BCL6), which can be gleaned from the subsequent statement:
"MYC translocations occur concurrently with BCL2 translocations in 57-87% of cases and with BCL6 translocations in 5-30% of cases. MYC, BCL2 and BCL6 translocations ("triple hit") are present in 7-15%[7][8][9]"
This article is also (unfortunately) now out of date given the removal of BCL6 from the HGBL definition in the 2022 WHO revision.