Although most acquired mutations associated with RA resistance were point mutations in PML-RARA, we identified a novel seven amino acid deletion mutation (p.K227_T233del) as well as a point mutation, p.R217S, in the RARA region of PML-RARA from an RA-resistant APL patient; however, the biological significance of these mutations was not analyzed. This evidence concerns the gene PML and acute promyelocytic leukemia.