Analysis of FLT3-ITD integration sites from 282 FLT3-ITD mutations
| Localization of ITD integration . | No. of ITDs . | Median ITD size, bp* . | Median ITD/WT ratio† . |
|---|---|---|---|
| JMD, AA 572-603 | 148 | 33 | 0.57775422 |
| Hinge region of JMD, AA 604-609 | 48 | 42 | 0.52208369 |
| Beta1-sheet, AA 610-615 | 73 | 60 | 0.58653097 |
| Nucleotide binding loop, AA 616-623 | 7 | 81 | 0.4269041‡ |
| Beta2-sheet, AA 624-630 | 4 | 96 | ‡ |
| 3′ of beta2-sheet, AA > 630 | 2 | 107 | ‡ |
| Localization of ITD integration . | No. of ITDs . | Median ITD size, bp* . | Median ITD/WT ratio† . |
|---|---|---|---|
| JMD, AA 572-603 | 148 | 33 | 0.57775422 |
| Hinge region of JMD, AA 604-609 | 48 | 42 | 0.52208369 |
| Beta1-sheet, AA 610-615 | 73 | 60 | 0.58653097 |
| Nucleotide binding loop, AA 616-623 | 7 | 81 | 0.4269041‡ |
| Beta2-sheet, AA 624-630 | 4 | 96 | ‡ |
| 3′ of beta2-sheet, AA > 630 | 2 | 107 | ‡ |
Categorization of the domains was according to Griffith et al.12
ITD indicates internal tandem duplication; bp, base pair; WT, wild type; JMD, juxtamembrane domain; and AA, amino acid.
FLT3-ITD size was strongly correlated with the insertion site, in that the more C-terminal the location of the insertion site, the longer the size of the inserted fragment (P < .001).
No significant association between mutant to wild-type ratio according to the functionally categorized FLT3-ITD groups (P = .26).
The value 0.4269041 is the combined median ITD/WT ratio for nucleotide binding loop, beta2-sheet, and 3′ of beta2-sheet due to the low number of insertion sites in these regions.