Relationship between gene silencing and CpG island hypermethylation in JMML. (A) Results of RT-PCR to detect the mRNA expression of BMP4, CALCA, CDKN2B, and RARB in peripheral blood cells from 4 JMML patients (patients D360, D359, D651, and D341) and from 3 healthy controls (patients N1, N11, and N13). (B) mRNA expression levels of the RARB gene (left; N = 33) and the CDKN2B gene (right; N = 13) in JMML PB MNCs in relation to CpG island methylation. Expression levels were measured by quantitative RT-PCR and CpG methylation was measured by MassARRAY. The average RARB mRNA expression in blood cells from 5 healthy controls was used as calibrator and was set to 1.0.