Characteristics of c-Kit and PDGF-Rα/β expression in peripheral blood and bone marrow at baseline
PN . | % c-kit+ blasts PB . | % c-kit+ blasts BM . | c-kit (IRS) . | phospho-c-kit (IRS) . | phospho-akt . | PDGFRα (IRS) . | PDGFRβ (IRS) . |
|---|---|---|---|---|---|---|---|
| 1 | ND | 42 | 3 × 3 (9) | 3 × 3 (9) | + | 2 × 1 (2) | 2 × 1 (2) |
| 2 | 22 | 32 | 4 × 3 (12) | 4 × 2 (8) | (+) | 4 × 1 (4) | 4 × 1 (4) |
| 3 | 20 | 86 | 4 × 3 (12) | 3 × 2 (6) | (+) | 2 × 2 (4) | 4 × 3 (12) |
| 4 | 31 | 27 | 3 × 3 (9) | 3 × 2 (6) | (+) | 3 × 2 (6) | 3 × 2 (6) |
| 5 | 43 | 46 | 3 × 2 (6) | 3 × 1 (3) | (+) | 3 × 3 (9) | 3 × 3 (9) |
| 6 | 81 | 92 | 3 × 2 (6) | 2 × 2 (4) | ++ | 2 × 2 (4) | 3 × 2 (6) |
| 7 | 71 | 71 | 4 × 3 (12) | 2 × 2 (4) | (+) | 3 × 2 (6) | 4 × 2 (8) |
| 8 | ND | 94 | 2 × 3 (6) | 2 × 3 (6) | +++ | 2 × 3 (6) | 4 × 3 (12) |
| 9 | 94 | 90 | 4 × 3 (12) | 4 × 3 (12) | ++ | 3 × 2 (6) | 4 × 2 (8) |
| 10 | 41 | 41 | 4 × 3 (12) | 4 × 3 (12) | ++ | 3 × 2 (6) | 4 × 3 (9) |
| 11 | ND | 96 | 2 × 2 (4) | 2 × 2 (4) | ND | 2 × 2 (4) | 2 × 2 (4) |
| 12 | 75 | 80 | 2 × 3 (6) | 2 × 2 (4) | (+) | 2 × 1 (2) | 3 × 3 (9) |
| 13 | 44 | 50 | ND | ND | ND | ND | ND |
| 14 | ND | 59 | 2 × 2 (4) | 2 × 2 (4) | (+) | 3 × 2 (6) | 3 × 2 (6) |
| 15 | 88 | 84 | 1 × 3 (3) | 1 × 3 (3) | (+) | 3 × 2 (6) | 3 × 3 (9) |
| 16 | 74 | ND | 2 × 1 (1) | 2 × 1 (2) | ((+)) | 2 × 2 (4) | 2 × 2 (4) |
| 17 | 37 | 43 | 1 × 3 (3) | 1 × 2 (2) | +++ | 3 × 3 (9) | 4 × 3 (12) |
| 18 | 26 | 43 | 2 × 2 (4) | 2 × 1 (2) | ++ | 2 × 1 (2) | 2 × 2 (4) |
| 19 | 5 | 31 | 1 × 2 (2) | 2 × 2 (4) | ND | 2 × 2 (6) | 2 × 2 (6) |
| 20 | 22 | 40 | 1 × 2 (2) | 1 × 1 (1) | ND | 2 × 3 (6) | 2 × 1 (2) |
| 21 | 65 | 63 | 1 × 1 (1) | 1 × 1 (1) | + | 2 × 2 (4) | 2 × 2 (4) |
| Median | 43.5 | 54.5 | 6 (IRS) | 4 (IRS) | NA | 6 (IRS) | 6 (IRS) |
PN . | % c-kit+ blasts PB . | % c-kit+ blasts BM . | c-kit (IRS) . | phospho-c-kit (IRS) . | phospho-akt . | PDGFRα (IRS) . | PDGFRβ (IRS) . |
|---|---|---|---|---|---|---|---|
| 1 | ND | 42 | 3 × 3 (9) | 3 × 3 (9) | + | 2 × 1 (2) | 2 × 1 (2) |
| 2 | 22 | 32 | 4 × 3 (12) | 4 × 2 (8) | (+) | 4 × 1 (4) | 4 × 1 (4) |
| 3 | 20 | 86 | 4 × 3 (12) | 3 × 2 (6) | (+) | 2 × 2 (4) | 4 × 3 (12) |
| 4 | 31 | 27 | 3 × 3 (9) | 3 × 2 (6) | (+) | 3 × 2 (6) | 3 × 2 (6) |
| 5 | 43 | 46 | 3 × 2 (6) | 3 × 1 (3) | (+) | 3 × 3 (9) | 3 × 3 (9) |
| 6 | 81 | 92 | 3 × 2 (6) | 2 × 2 (4) | ++ | 2 × 2 (4) | 3 × 2 (6) |
| 7 | 71 | 71 | 4 × 3 (12) | 2 × 2 (4) | (+) | 3 × 2 (6) | 4 × 2 (8) |
| 8 | ND | 94 | 2 × 3 (6) | 2 × 3 (6) | +++ | 2 × 3 (6) | 4 × 3 (12) |
| 9 | 94 | 90 | 4 × 3 (12) | 4 × 3 (12) | ++ | 3 × 2 (6) | 4 × 2 (8) |
| 10 | 41 | 41 | 4 × 3 (12) | 4 × 3 (12) | ++ | 3 × 2 (6) | 4 × 3 (9) |
| 11 | ND | 96 | 2 × 2 (4) | 2 × 2 (4) | ND | 2 × 2 (4) | 2 × 2 (4) |
| 12 | 75 | 80 | 2 × 3 (6) | 2 × 2 (4) | (+) | 2 × 1 (2) | 3 × 3 (9) |
| 13 | 44 | 50 | ND | ND | ND | ND | ND |
| 14 | ND | 59 | 2 × 2 (4) | 2 × 2 (4) | (+) | 3 × 2 (6) | 3 × 2 (6) |
| 15 | 88 | 84 | 1 × 3 (3) | 1 × 3 (3) | (+) | 3 × 2 (6) | 3 × 3 (9) |
| 16 | 74 | ND | 2 × 1 (1) | 2 × 1 (2) | ((+)) | 2 × 2 (4) | 2 × 2 (4) |
| 17 | 37 | 43 | 1 × 3 (3) | 1 × 2 (2) | +++ | 3 × 3 (9) | 4 × 3 (12) |
| 18 | 26 | 43 | 2 × 2 (4) | 2 × 1 (2) | ++ | 2 × 1 (2) | 2 × 2 (4) |
| 19 | 5 | 31 | 1 × 2 (2) | 2 × 2 (4) | ND | 2 × 2 (6) | 2 × 2 (6) |
| 20 | 22 | 40 | 1 × 2 (2) | 1 × 1 (1) | ND | 2 × 3 (6) | 2 × 1 (2) |
| 21 | 65 | 63 | 1 × 1 (1) | 1 × 1 (1) | + | 2 × 2 (4) | 2 × 2 (4) |
| Median | 43.5 | 54.5 | 6 (IRS) | 4 (IRS) | NA | 6 (IRS) | 6 (IRS) |
FACS was used to determine percentage of c-kit+ blasts in PB and BM. IHC was used to determine IRS of c-kit, phospho-c-kit, phospho-akt, PDGFRα, and PDGFRβ.
Immunoreactivity on leukemic blasts in bone marrow biopsies was scored from 0 to 12, taking into account the percentage of receptor-positive blasts and their staining intensity [IRS (0-12) = RP (0-4) × SI (0-3)].
In normal hematopoietic cells as lymphocytes, plasma cells and normoblasts the IRS was 0 for c-kit, phospho-c-kit and phospho-Akt.
PN indicates patient number; FACS, fluorescence activated cell sorter; IRS, immunoreactivity score; IHC, immunohistochemistry; ND, not determined; NA, not available; symbols ((+)), (+), +, ++, +++ indicate very low, low, moderate, high, and very high staining signals obtained by IHC analysis, respectively.