Pre-rRNA expression in CD34⁺ cells from healthy and MDS BM. (A) Levels of pre-rRNA expression were determined in CD34⁺ cells from 5 healthy controls (circles) and 6 MDS patients (squares) in a single representative experiment. GAPDH was used as the internal control and samples were run in triplicate. (B) Cumulative data showing levels of pre-rRNA in CD34⁺ cells from 10 healthy control and 22 MDS samples. GAPDH was used as the internal control. The ends of the whiskers represent minimum and maximum values and the bar indicates the median value (50th percentile). Significance was determined using the Mann-Whitney test.