The authors retract the March 18, 2010, article cited above. It contains multiple inaccurate and inappropriately duplicated β-actin RT-PCR gel images. The last author, Naoki Mori, takes full responsibility for the inappropriate duplication and manipulation of the figures in this paper, and states that none of the coauthors were involved in or aware of these events. He apologizes to the readers, reviewers, and editors of Blood for publishing these erroneous images.

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