Frequency of CAFCs after 9 days of culture in different conditions. Either primary CD34⁺ cells or cells cultured in a cytokine combination in the presence or absence of 5azaD and TSA for 9 days were analyzed for their ability to form CAFCs. The number of CAs was expressed out of 10 000 cells plated. CAFC frequency was computed using minimization by regression to the cell number at which 37% of wells showed negative CAFC growth with 95% statistical precision. The bar graph represents mean ± SE of 2 experiments done in limiting dilution where each concentration of cells is tested 24 times.