[Clinical significance of FLT3 internal tandem duplication in acute myeloid leukemia with chromosome abnormality].

This study was to explore the clinical significance of FLT3 internal tandem duplication (FLT3/ITD) in acute myeloid leukemia (AML) with chromosome abnormality. Karyotypes in 125 AML patients were analyzed by R banding technique. Using genomic PCR and sequencing, FLT3/ITD mutation in AML patients with or without chromosome abnormity were examined. The results indicated that chromosome abnormality with various types was found in 46 out of 125 samples, the positive rate was 36.8%. The positive rate in different chromosome subtypes included M(0) 57.14%, M(1) 55.56%, M(2) 38.71%, M(3) 50.0%, M(4) 50.0%, M(5) 30.77%, M(6)/M(7) 10.0% and M(7) 18.75% respectively. In various chromosome abnormality types, t (16, 21) occurred in 9 samples with highest rate 19.78%, and the others were t (8, 21) in 7 samples, t (4, 11) in 6 samples with the occurrence rate 15.22%, 13.04% respectively. Besides, t (6, 9) was detected in 3 samples which was seldom found domestically, the positive rate was 6.52%. In 79 samples without chromosome abnormality, FLT3 gene expression was detected in 56 samples, the positive rate was 70.89%. In 46 samples with chromosome translocation, FLT3 gene expression could be detected in 31 samples, the positive rate was 67.39%. The difference between them was no significant (p > 0.05). And the FLT3/ITD mutation rates in these two groups were 11.39% and 24.09% respectively, whose difference was statistically significant (p < 0.05). Clinical data showed that the difference was no statistically significant (p > 0.05) in leukocyte counting and Hb assay in peripheral blood as well as leukocyte ratio in bone marrow of these two groups with or without chromosome abnormality. Most FLT3/ITD mutation patients with or without chromosome abnormality died in short time, the difference of death rate was not statistically significant between these two groups (p > 0.05) while the life span of FLT3/ITD mutation patients with chromosome abnormality was even shorter than the other. The difference between them was statistically significant (p < 0.05). It is concluded that prognosis is relatively poor in FLT3/ITD mutation patients with chromosome abnormality. FLT3/ITD mutation may be an important marker for poor prognosis of AML.