DOES THE PATTERN OF CLONAL EVOLUTION IN THE KARYOTYPE OF PATIENTS WITH ACUTE MYELOID LEUKEMIA AND MYELODYSPLASTIC SYNDROMES DEPEND ON THE TYPE OF THE PRIMARY CHROMOSOMAL ABERRATIONS?

The aim of our study was to define if the type of primary chromosomal aberrations (CA) of the karyotype of patients with Acute myeloid leukemia (AML) and Myelodysplastic syndromes (MDS) determines the way and the rate of karyotype development. Conventional cytogenetic analysis was carried out on 248 AML and 105 MDS patients at diagnosis. Clonal evolution (CE) was found in 40% (51 of 128) of AML patients and in 47.5% (19 of 40) of MDS patients having CA in their karyotype. The first pattern we established was for the most frequent CA which initiate CE in 28 patients with a complex karyotype. These CA were non-balansed rearrangements in the following regions: 5q, 7q, 11q, 3q, monosomy 5, monosomy 7. The second pattern of CE was regarding the most frequent aneuploidias (+8, +11, +21, -Y, and the third pattern concerned balanced CA. We found significant difference in the distribution of karyotypes in different stages of progression between the first and the other two groups (p < 0.001). No statistical difference was found between the patterns in the second and the third group CA (p > 0.5).

IS THE AMPLIFICATION OF c-MYC, MLL AND RUNX1 GENES IN AML AND MDS PATIENTS WITH TRISOMY 8, 11 AND 21 A FACTOR FOR A CLONAL EVOLUTION IN THEIR KARYOTYPE?

The aim of our study was 1) to define if the amplification of c-MYC, MLL and RUNX1 genes is related to the progressive changes of the karyotype in patients with AML and MDS with trisomy 8, 11 and 21 (+8, +11 and +21) in bone marrow and 2) can that amplification be accepted as part of the clonal evolution (CE). Karyotype analysis was performed in 179 patients with AML or MDS with the different chromosomal aberrations (CA) aged 16-81. The findings were distributed as follow: initiating balanced CA (n = 60), aneuploidia (n = 55), unbalanced CA (n = 64). Amplification of c-MYC, MLL and RUNX1 genes by means of fluorescence in situ hybridization (FISH) was found in 35% (7 out of 20) of AML and MDS patients with +8, +11 u +21 as single CA in their karyotype; in 63.6% of pts (7 out of 11)--with additional numerical or structural CA and in 75% (9 out of 12)--with complex karyotype. We assume that the amplification of the respective chromosomal regions in patients with +8, +11 and +21 is related to CE. Considering the amplification as a factor of CE, we established 3 patterns of karyotype development depending on the type of the initiating CA in it. Significant statistical differences were found between the three patterns regarding the karyotype distribution in the different stages of progression (p < 0.001).

Wilms' tumor protein and FLT3-internal tandem duplication expression in patients with de novo acute myeloid leukemia.

Bone marrow samples of 30 patients with de novo adult acute myeloid leukemia (AML) were analyzed for Wt1 and FLT3-internal tandem duplication (FLT3-ITD) expression measured by western blot and reverse transcription-polymerase chain reaction analysis, respectively. Wt1 was detected in 53·3% of AML patients (16/30), while FLT3-ITD in 23·3% (7/30). The high Wt1 expression correlated with the presence of FLT3-ITD (P = 0·014) and lower rate of complete remission (P = 0·023). The cumulative survival in AML patients was affected significantly by the presence of FLT3-ITD, being lower in the FLT3-ITD (+) group (6·0±2·4 months) compared to the FLT3-ITD (-) patients (17·9±3·3; P = 0·04). The expression of FLT3-ITD could probably activate Wt1 expression in AML blast cells and thus might contribute to its oncogenic function to provide cells with survival advantages in vivo. The detection of both molecular markers (Wt1 and/or FLT3-ITD) may be helpful in defining high risk AML patients that need special therapeutic strategies.

Amplification of c-MYC and MLL Genes as a Marker of Clonal Cell Progression in Patients with Myeloid Malignancy and Trisomy of Chromosomes 8 or 11.

Gene amplification (amp) is one of the basic mechanisms connected with overexpression of oncogenes. The c-MYC (located in 8q24) and MLL (located in 11q23) are the most often over represented genes that lead to a rapid proliferation of the affected cell clone in patients with myeloid neoplasms. Assessment of the level of amp c-MYC or amp MLL in the cases with trisomy 8 (+8) or trisomy 11 (+11) and myeloid malignances is necessary for a more precise estimation of the disease progression. A total of 26 patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) were included in the study: 18 with +8, six with +11 and two with complex karyotypes suspected of the partial trisomy. Routine cytogenetic analysis and fluorescent in situ hybridization (FISH) were applied to indicate the chromosome alterations and genes amp in the bone marrow cells. Amp c-MYC was observed in 12 from 18 (66.7%) patients with +8. All the patients with +11 demonstrated a different level of amp MLL. In most of the cases with MDS (9/10), the coincidence of the +8 or +11 with amp c-MYC or amp MLL, respectively, leads to transformation to AML and/or short overall survival. Our data suggest that amp c-MYC and amp MLL develop in conformity with +8 and +11, especially in cases with progressive deviations in the karyotype as an aggressive expansion of an aberrant cell clone and appearance of additional chromosome anomalies.