Abnormal serum free light chain ratio predicts poor overall survival in mantle cell lymphoma

Serum free light Chain (sFLC) ratios have been correlated with survival outcomes in Hodgkin and non-Hodgkin lymphoma subtypes. This study was undertaken to investigate the prognostic impact of abnormal sFLC ratios in mantle cell lymphoma (MCL). two patient cohorts were analysed for sFLC parameters: a preliminary retrospective cohort and a uniformly treated cohort of 20 relapsed/refractory MCL patients, enrolled in a phase II clinical trial of single agent lenalidomide treatment. 52% of patients had an abnormality of one or more sFLC parameter (71% of the first cohort and 40% of the second cohort). In cohort two, a high baseline SFLC ratio correlated with poorer overall survival (OS) compared to a low/normal ratio (median OS: 1.4 months vs. 19 months respectively; P = 0.001). For patients presenting with an elevated sFLC ratio at trial entry a rise of >35% in the sFLC ratio correlated with disease progression and a sFLC ratio of >2x normal at trial entry correlated with aggressive disease. These data are the first to show a clear clinical correlation between sFLC ratios and survival outcomes in a uniformly treated cohort of MCL patients. We suggest that these markers may be useful in managing patients with MCL in the future.