To determine if promoter hypomethylation is cancer-specific or is present in other normal cell types, we evaluated the methylation status of promoters in a range of B cell subsets (immature B cells, mature B cells, B-1a, CD19+, follicular B cells, and marginal zone B cells), T cells (CD4 and CD8), and myeloid cells. The gene discussed is CD4; the disease is cancer.