Proportion of the Wt- and mutant-FLT3 fragments. Representative results of RT-PCR (A) and genomic PCR (B) in 7 AML samples with FLT3/ITD are shown. The proportion given for each sample denotes the relative intensity of Wt-FLT3 and FLT3/ITD fragments. Each relative proportion obtained by RT-PCR was consistent with that by genomic PCR. (C) The correlation between the expression levels of the Wt-FLT3 and FLT3/ITD transcripts in 34 AML samples with FLT3/ITD is shown. Four AML samples, which lost the Wt-FLT3 allele, were excluded from this analysis. Both expression levels were closely correlated (P < .0001 by the Spearman rank correlation test).