TABLE 1.
Main pathological characteristics in patients with diffuse large B‐cell lymphoma (training set)
| Characteristic | Frequency (%) | |
|---|---|---|
| Histological | ||
| CD3+ | 0s | (1.6) |
| CD5+ | 12/129 | (9.3) |
| CD20+ | 129/131 | (98.5) |
| CD10+ | 39/130 | (30.0) |
| BCL6+ | 88/129 | (68.2) |
| MUM1+ | 89/129 | (69.0) |
| Non‐GCB (Hans classifier) | 82/129 | (63.6) |
| BCL2+ | 89/129 | (69.0) |
| EBV EBER+ | 10/125 | (7.6) |
| RGS1‐high | 64/108 | (59.3) |
| MYC‐high | 62/119 | (52.1) |
| Molecular | ||
| BCL2 split (FISH) | 13/121 | (10.7) |
| MYC split (FISH) | 13/124 | (10.5) |
| BCL6 split (FISH) | 18/106 | (17.0) |
| BCL2 and MYC split (FISH) | 2/119 | (1.7) |
| BCL2 IHC+ and MYC‐IHC‐high (double expressor) | 39/123 | (31.7) |
| MYC t+ and/or MYC‐IHC‐high | 67/132 | (50.8) |
| High grade B‐cell lymphoma (MYC t+ and BCL2 t+ and/or BCL6 t+) | 5/125 | (4.0) |
| MYD88 L265P mutation | 12/121 | (9.9) |
The cut‐off for positivity for the immunohistochemical (IHC) markers for B lymphocytes of DLBCL using the Hans algorithm (CD10, BCL6, IRF4/MUM1) was set at the conventional 30%. BCL2 was considered positive if more than 50% of the tumoral cells were positive. High regulator of G‐protein signaling 1 (RGS1) expression associates with poor prognosis in DLBCL. RGS1‐high corresponds to expression 2‐3+ as we have previously described. 21 MYC translocation positive cases positively correlated with higher IHC expression for MYC protein (Fisher’s exact test, P = .003); MYC‐high cut‐off was 40%, and after digital image quantification was set at 22%.
Abbreviations: EBER, EBV‐encoded small RNA; EBV, Epstein–Barr virus; GCB, germinal center B cell‐like.