Protein profiling by reverse phase protein array (RPPA) in classical hairy cell leukemia (HCL) and HCL-variant.

Classical hairy cell leukemia (HCL-c) and HCL variant (HCL-v) are recognized as separate entities with HCL-v having significantly shorter overall survival. Proteomic studies, shown to be prognostic in various forms of leukemia, have not been performed in HCL. We performed reverse phase protein array-based protein profiling with 384 antibodies in HCL-c (n = 12), HCL-v (n = 4), and normal B-cells (n = 5) samples. While HCL could be distinguished from normal based on unsupervised hierarchical clustering, overlap in protein expression patterns was seen between HCL-c and HCL-v, with ∼10% of the proteins being differentially expressed, suggesting potential therapeutic targets.