SOX7 expression was downregulated in myeloid malignancies. (A) SOX7 transcript (upper) and protein (lower) were downregulated in AML cell lines (K562, KG-1, ML2, MV4-11, MOLM-13, and THP-1) as compared to Nalm20 (N-20). (B) Expression of SOX7 transcript was measured by quantitative real-time RT-PCR in AML (n = 35), normal UCB CD34⁺ cells (n = 11), and ALL (n = 13), which was carried out by SYBR Green method in a StepOnePlus thermal cycler (Applied Biosystems, Foster City, CA). SOX7 was significantly downregulated in AML samples. The bars show the mean of expression, and comparisons were evaluated by unpaired Student t test. ***P < 0.001, n.s., not significant. (C) SOX7 protein was more commonly expressed in normal BM samples compared to primary AML samples. (D) Bisulfite sequencing on leukemia cell lines (left). Robust hypermethylation on SOX7 gene was observed in all myeloid leukemia cell lines but not in the precursor B-cell ALL cell line (Nalm20). DNA methylation could also be demonstrated in AML samples 1 to 6 but not in normal UCB CD34⁺ cells (right). Black dots, white dots, and arrows indicate methylated and unmethylated cytosine in CpG and the position of transcription start site, respectively. (E) DNA methylation of SOX7 in 27 AML and 8 normal BM samples and in the ALL cell line Nalm20 was demonstrated by MS-PCR. M, methylated allele; U, unmethylated allele.