rearrangement is associated with a distinctive immunophenotype but not outcome in patients with systemic ALK-negative anaplastic large cell lymphoma.

DUSP22 rearrangement (R) has been associated with a favorable outcome in systemic ALK-negative anaplastic large cell lymphoma (ALCL). However, a recent study found that patients with DUSP22-R ALK-negative ALCL have a poorer prognosis than was reported initially. In this study, we compared the clinicopathological features and outcomes of patients with ALKnegative ALCL with DUSP22-R (n=22) versus those without DUSP22-R (DUSP22-NR; n=59). Patients with DUSP22-R ALCL were younger than those with DUSP22-NR neoplasms (P=0.049). DUSP22-R ALK-negative ALCL cases were more often positive for CD15, CD8, and less frequently expressed pSTAT3Tyr705, PD-L1, granzyme B and EMA (all P<0.05). TP63 rearrangement (TP63-R) was detected in three of the 66 (5%) ALK-negative ALCL cases tested and none of these cases carried the DUSP22-R. Overall survival of patients with DUSP22-R ALCL was similar to that of the patients with DUSP22-NR neoplasms regardless of International Prognostic Index score, stage, age, or stem cell transplantation status (all P>0.05), but was significantly shorter than that of the patients with ALK-positive ALCL (median overall survival 53 months vs. undefined, P=0.005). Five-year overall survival rates were 40% for patients with DUSP22-R ALCL versus 82% for patients with ALK-positive ALCL. We conclude that DUSP22-R neoplasms represent a distinctive subset of ALK-negative ALCL. However, in this cohort DUSP22-R was not associated with a better clinical outcome. Therefore, we suggest that current treatment guidelines for this subset of ALK-negative ALCL patients should not be modified at present.