RET and leukemia: Methylated genes in cluster 1 include proteins highly expressed in neural systems (CHGA, GABRB3, GAS7, FEV), strongly related to leukemia (TCL1A, FLT3, FLT4), involved in cell growth and proliferation (EGFR, WT1, SMO, IGF2, RET), and transcription factors involved in diverse or unknown functions (PAX3, PAX7, HOXC13, ZIM2).