Serum soluble interleukin-2 receptor level at diagnosis predicts transformation in patients with follicular lymphoma.

We evaluated 121 patients with follicular lymphoma (FL) and analyzed the association between the soluble interleukin-2 receptor (sIL-2R) level at diagnosis and the cumulative incidence of transformation. By a receiver-operating characteristic analysis, we determined a cutoff value of sIL-2R for transformation at 4360 U/mL to classify patients into two groups. Patients in the high sIL-2R group showed a shorter progression-free survival (PFS) and shorter disease-specific survival (DSS) (p < 0.001 and p = 0.018). Furthermore, the cumulative incidence of transformation in the high sIL-2R group was higher than that in the low sIL-2R group (40.9% vs. 7.3% at 5 years, p < 0.001). In a multivariate analysis, high sIL-2R was an independent predictive risk factor for transformation (HR 7.42, 95% CI: 2.75-20.0, p < 0.001). This study showed that the sIL-2R level at diagnosis may be a prognostic factor for transformation, PFS, and DSS in patients with FL.