TP53 and acute promyelocytic leukemia: Contrariwise, the other APL cases in Cluster 2 showed an enhanced expression of ATRA-regulated genes that were found more related to cell cycle regulation, Myc and p53 transcriptional response, as revealed by MSIgDB analysis (Figure 5C); a large fraction of these genes in Set B were downregulated by ATRA treatment of NB4 cells (555/941; 58.9%; Table S6).