ABC transporters are not down modulated following osteogenic differentiation of USSCs. The expression levels on day 0 are set at 1 and the fold difference in expression at other time points is given on day 1, day 3 and day 7. Significant threshold is 3-fold induction or downregulation and is indicated by the grey lines. Detection count of each gene in 6 USSC samples is indicated on the bottom of the figure for each transporter. Only transporters with detection frequency above 5/6 in USSCs are included.