The SLC19A1 assay (designed at the edge of the CpG island − 700 base pairs from the transcription start site) showed median methylation of 64% (range, 21 to 83%) in pre-decitabine tumor samples, compared to 18% in patient blood samples, 10% in normal control adult blood samples, 9% in control umbilical cord blood samples, and 63% in leukemia cell lines. Here, SLC19A1 is linked to leukemia.