In our examination of the different histological subtypes of aggressive B-cell lymphomas, PMBCL stood out with significantly lower surface CD79b expression compared to others (median 0.8% IQR 0–48.5 vs. 80% IQR 24–97, respectively, p = 0.0005). The gene discussed is CD79B; the disease is B-cell non-Hodgkin lymphoma.