MYC protein expression scoring and its impact on the prognosis of aggressive B-cell lymphoma patients

This study examined the reproducibility of MYC and BCL-2 immunohistochemical scoring as well as the impact of higher expression of both proteins (double expressor status, DE) on survival and progression in a large retrospective cohort of aggressive B-cell lymphoma patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) or R-CHOP-like regimens with a median follow up of 67 months (range 0–138). We also investigated possible MYC protein expression cut offs with the highest reproducibility among pathologists and predictability of gene translocation. We showed that immunohistochemistry (IHC) for MYC and BCL-2 is highly reproducible when cut-off values of >70% for MYC and >50% for BCL-2 are used. This threshold not only predicts the presence of rearrangements (with respect to MYC), but is also clinically valuable. In fact, it identifies a subset of patients who are poor responders and who may benefit from alternate therapeutic strategies