Testa et al. in 2002 reported the results of a first systematic analysis of CD123 in AML, showing an overexpression in about 45% of cases associated with increased cycling activity of leukemic blasts, increased cellularity (white blood cell count) at diagnosis, and increased responsiveness to cell signaling triggered by IL3 and poor prognosis [14]. This evidence concerns the gene IL3RA and acute myeloid leukemia.