Human ether-a-go-go related gene (herg) encoding HERG K(+) channel has been 
demonstrated in many previous studies with its association to cell cycle 
progression and growth in tumor cells. The upregulated expression of HERG K+ 
channels was determined in different tumor types. Furthermore, not only 
full-length transcript herg1 but also a truncated isoform herg1b was shown to be 
expressed in cancer cells. In this study, the expression levels of herg1 and 
herg1b and the impact of K897T mutation on their expressions were investigated 
in pediatric acute myeloid leukemia (pAML). Expression levels of herg1 and 
herg1b isoforms were analyzed by quantitative real time polymerase chain 
reaction (PCR) in pAML patients together with healthy donors, and their 
expressions were confirmed by western blotting. The 2690 A>C nucleotide 
variation in KCNH2 gene corresponding to K897T amino acid change was analyzed by 
PCR followed by restriction enzyme digestion. herg1b overexpression was observed 
in tumor cells compared to healthy controls (P = .0024). However, herg1 
expression was higher in healthy control cells than tumor cells (P = .001). The 
prevalence of polymorphic allele 897T was 26% in our patient group and 897T 
carriers showed increased herg1b expression compared to wild-type allele 
carriers. Our results demonstrate the presence of the increased levels of herg1b 
expression in pAML. In addition, we report for the first time that, pAML 
subgroup with HERG 897K/K genotype compared to 897K/T and T/T genotypes express 
increased levels of herg1b. In conclusion, HERG 897K/K genotype with increased 
level of herg1b expression might well be a prognostic marker for pAML.