RNASE2 and Chronic Eosinophilic Leukemia, Not Otherwise Specified: Shortly thereafter, Slifman and colleagues [22] found that EDN was an active ribonuclease, and was capable of generating soluble ribonucleotides from insoluble tRNA to an extent similar to that achieved by bovine pancreatic RNase A. The full nucleotide sequence of EDN was assembled from cDNAs identified in libraries generated from bone marrow RNA from an individual with eosinophil leukemia [23] and from cells of the HL-60 promyelocyte line [24].