Furthermore, our results showed that lower concentration (0.25-2.0 μM) of ATO induced differentiation of TBLR1-RARα positive APL cells after a long-time culture, whereas higher concentration (4.0-8.0 μM) of ATO induced apoptosis of TBLR1-RARα positive APL cells. This evidence concerns the gene RARA and acute promyelocytic leukemia.