Role of molecular-genetic abnormalities in pathogenesis and risk stratification of multiple myeloma.

Over the past decades the studies have greatly improved our understanding of the molecular basis of multiple myeloma (MM) and mechanisms of disease progression. The majority of the most widespread chromosomal aberrations, revealing in MM, has independent predictive value and influence on a choice of optimal treatment. There were observed 190 MM patients in hematologic hospitals of St. Petersburg. Genetic anomalies (GA) were detected at 3l,3% of patients and did not depend on their age. Patients with ISS III had a detectability of GA higher than with ISS II and ISS I (48,°% (24/5°), 2l,2% (7/33) and 27,6% (8/29)). Translocation t(ll;l4) was found in 23,3% (3O/129) patients; dell3q - 20,8% (27/13°); dell7p - at 8,4% (7/83); t(4;l4) - at 6,9% (9/13O), that allowed to stratify patients in groups of risk according to mSMART version l. O and 2. O. Median overall survival (OS) modified mSMART l. O in group of standard risk was 7° months, high risk - 47,l months. Median OS mSMART 2. O in group of standard risk was 7° months, intermediate risk - 47 months, high risk - 45 months. OS did not depend on age, clinical manifestations, treatment and other factors.

[Heterogeneity of acute myeloid leukemia with the translocation t(8;21)(q22;q22)].

AIM: To characterize the clinical and hematological variability of acute myeloid leukemia (AML) with t(8;21) and to identify the signs associated with the likelihood of its relapse. SUBJECTS AND METHODS: The results of examining 44 patients aged 11 to 70 years were analyzed; the efficiency of treatment was evaluated in 36. Their karyotypes were studied using the standard GTG method. Polymerase chain reaction (PCR) was employed to assess the mutational status of the FLT3, NPM1, NRAS and c-Kit genes. Qualitative PCR was used to reveal the chimeric transcript RUNX1/RUNX1T1. RESULTS: The M2 variant was verified using the French-American-British classification in 82% of cases. One patient was diagnosed with secondary AML. Additional chromosomal aberrations were found in 50% of the patients. The most common breakages were loss of one of the sex chromosomes (34.1%) and damage of chromosome 9 (16.6%). Gene mutations were detected in single cases. Following 2 7+3 induction chemotherapy (CT) cycles, complete remission (CR) was achieved in 97% of cases (3 patients with cytopenia died). Eight (25%) patients developed a relapse mainly within the first 7 months after achieving CR. The characteristic signs of relapse cases were the inefficiency of the first cycle of remission induction (RI), the absence of high-dose consolidation, damage of chromosome 9, D816V mutation in exone 17 of the c-Kit gene. Antirecurrent CT was ineffective in 5 patients. The median overall survival (OS) in patients with early recurrence was 10 months. That in the patients who were recorded to have CR was not achieved; 5-year OS was 57.8%. Chromosome 9 aberration was ascertained to have a negative impact on OS parameters (p=0.003). CONCLUSION: Patients with AML with t(8;21) is a group heterogeneous with respect to age, the morphological nature of blast cells, the pattern of the disease, the presence and type of additional chromosomal aberrations, mutations in individual genes, and clinical course. Those who are unresponsive to the first RI cycle and have additional chromosome 9 damages should be regarded as potential candidates for allogeneic hematopoietic stem cell transplantation.

[The specific features of the immunophenotype of blast cells in patients with de novo normal karyotype acute myeloid leukemia and FLT3-ITD mutation].

AIM: To study the specific features of de novo acute myeloid leukemia (AML) with FLT3-ITD mutation. SUBJECTS AND METHODS: The results of examination were analyzed in 101 patients. Bone marrow morphological specimens were stained with Pappenheim stain. The karyotype was investigated using the standard GTG-banding method. Blast cells were immunotyped in a five-color analysis on a Cytomics FC 500 laser flow cytofluorometer. RESULTS: FLT3-ITD mutation was identified in 21 patients who had a varying morphological nature of blasts, different karyotype variants, and frequently additional NPM1 gene mutation. The distinctive property of 10 patients with normal karyotype and FLT3-ITD mutation (without NPM1 gene mutation) was the larger number of cases with high expression of HLA-DR and CD7 than in the control group that included 18 patients with normal karyotype AML without FLT3-ITD nutation: 50% versus 6.2% (p = 0.007) and 100% versus 55.6% (p = 0.014), respectively. CONCLUSION: Normal karyotype AML with FLT3-ITD mutation is a group that is homogeneous in the biological phenotype of leukemia cells.

[Cytogenetic profile in patients with primary myelodysplastic syndrome].

AIM: To analyze the prevalence of chromosome aberrations presented in the revised International Prognostic Scoring System (R-IPSS) in patients with de novo myelodysplastic syndrome (MDS). Subjects and methods. Chromosome aberrations were analyzed in 197 patients aged 14 to 86 years (median age 64 years) with de novo MDS. RESULTS: Karyotype abnormalities were revealed in 129 (65.5%) patients with de novo MDS. According to the IPSS criteria, the karyotypes found 52 (26.4%) patients were assigned to an intermediate prognostic group whereas in accordance with the R-IPSS guidelines, an intermediate karyotype group included chromosome abnormalities in 32 (16.2%) patients. Out of 5 R-IPSS prognostic types, the favorable karyotype group was the largest (48.2%). The very favorable and unfavorable karyotype groups comprised few patients with MDS: 3 and 3.6%, respectively. Despite the fact that it was not mentioned in the R-IPSS, a monosomal karyotype was verified in 24 (12.2%) patients There was a correlation of the (normal and complex) karyotype with bone marrow blast counts (r=0.469; p=0.000), but not with age. CONCLUSION: A variety of cytogenetic damages cannot identify the prognostic potential of all chromosome aberrations occurring in patients with MDS even if prognostic factors increased up to 5.

[Age-specific characteristics of acute myeloid leukemia karyotype].

AIM: To study distribution of some karyotype variants among patients of different age with acute myeloid leukemia (AML). MATERIAL AND METHODS: Distribution of balanced, normal, unbalanced, complex and monosomic karyotype among 244 patients with de novo AML in age groups 16-20, 21-30, 31-40, 41-50, 51-60, 61 and older was analysed. RESULTS: There is difference in frequency of balanced and complex karyotype in patients under and over 60 years. Number of AML patients with balanced aberrations including favourable variants t(8;21), t(15;17) and inv(16) falls after 60 years of age (6.7% versus 15.0% in patients aged 16-20 years; p < 0.001), while a complex karyotype occurs more frequently in AML patients at the age of 61 and older (56.8% versus 2.7% in the group 16-20 years; p < 0.001). With age, more frequently detected is the most unfavourable monosomic karyotype with aberrations similar to those in myelodysplastic syndrome (57.1% in patients aged 16-60 years and in 80.0% in the group of 61 years of age and over). CONCLUSION: Age-specific karyotype features detected may be explained by different biological mechanisms involved in leukosogenesis in young and elderly AML patients.

[Prognostic potential of morphological and cytogenetic indices in patients with myelodysplastic syndrome].

AIM: To examine prognostic potential of the number of bone marrow (BM) blasts and cell karyotype as risk factors of transformation of myelodysplastic syndrome (MDS) in acute myeloblastic leukemia AML. MATERIAL AND METHOD: The analysis of examination was made for 72 patients with primary MDS in the groups formed by number of blasts in BM, karyotype and IPSS variant. MDS was diagnosed by WHO criteria. Transformation into AML was established in blastosis > 20% in peripheral blood and/or BM. The karyotype was studied according to GTG technique. RESULTS: More frequent progression of MDS was seen in patients with blastosis > 10%, unfavourable karyotype and high IPSS risk. The least number of leukemic transformations occurred in karyotype of intermediate prognosis while disease-free survival in patients with karyotype of good prognosis was similar to that of patients with unfavourable karyotype. The number of blasts in BM and IPSS variant appeared to be prognostic markers of duration of leukemia-free survival in one-factor analysis. The multifactorial analysis found out one factor of MDS transformation in AML: number of blasts in BM puncture biopsy. CONCLUSION: Prognostic priority of the number of BM blasts as a risk factor of MDS progression compared to karyotype is explained by biological heterogenicity of MDS.