Analysis of allelic loss in FLT3-ITD–positive samples.
(A) FISH analysis of a patient with an allelic ratio of 3.65. Red signals denote the BAC 85P08 labeled with SpectrumRed, and the green signals indicate a commercial DNA FISH probe (LSI 13) containing the entire RB1 gene and regions telomeric to RB1 labeled with SpectrumGreen. Original magnification, × 125. (B) Results of the PCR assay to detect allelic loss at the FLT3 locus. The left graph denotes the results of the spiking experiment. A linear increase in the FLT3/HGH ratio was obtained after the addition of 1 to 3 pg BAC 85P08 DNA containing the FLT3 genomic locus,r2 = 0.9895. The right graph shows the comparison of the allelic ratios obtained in healthy donors (HD; n = 22), patients with FLT3 wt/mutant ratios greater than 2 (FLT3-ITD; n = 12), and an AML patient with monosomy 13 (−13).
