Bcr Unresponsiveness And 13q14 Duplication Underpin Spontaneous Disease Regression In Chronic Lymphocytic Leukemia

Spontaneous regression of chronic lymphocytic leukemia occurs in less than 2% of cases and the mechanisms that underlie this rare event remain largely unknown. We reviewed 1425 patients with CLL across 4 centers and identified 20 who underwent spontaneous disease regression without treatment over a median period of 8.6 years. This included 12 patients with complete and 8 with partial (> 50%) resolution of lymphocytosis and clinical features. Residual circulating CLL cells remained detectable in all cases and phenotypic, functional and genomic analyses were performed on the residual CLL clone, as well as stored cells where available, to investigate potential mechanisms underlying regression.