To this end we employed the CRY1 qRT-PCR assay to screen RNA samples isolated from a wide range of lymphoproliferative disorders including T prolymphocytic leukemia (T-PLL, n = 10), mantle cell lymphoma (MCL, n = 6), hairy cell leukemia (HCL, n = 3), multiple myeloma (MM, n = 8), plasma cell leukemia (PCL, n = 2) and B and T lineage acute lymphoid leukemia (n = 29 resp. This evidence concerns the gene CRY1 and plasma cell leukemia.