IPSS. (A) The original IPSS. (B) Overall survival and AML transformation curves for patients in the 4 IPSS risk groups. (C) Compared with the IPSS, the IPSS-R includes additional cytogenetic risk groups and describes more chromosomal abnormalities. It decreases the relative weight of elevated BM blast percentage and it considers cytopenias individually, with additional weight given to more severe cytopenias. (D) Overall survival and AML transformation curves for patients in the 5 IPSS-R risk groups.