L428 cells contain a small population of phenotypic B cells. (A) A percentage (0.3% ± 0.08%) of the cells coexpressed CD20 and lambda light chain, and (B) were CD30−. Treatment of the cell line with 0.5 μM decitabine for 72 hours increased the fraction of cells expressing (C) lambda light chain and (D) CD20 to 5% ± 1% of the total cells (P = .04). The data represent the mean ± SEM of 10 separate experiments.