[Multiple myeloma from the pathologist's perspective]. / Multiples Myelom aus Sicht der Pathologie.

BACKGROUND: Multiple myeloma (MM) is one of the most common hematological neoplasms and accounts for approximately 1% of human cancers. OBJECTIVES: Description of current diagnostics and classification of MM and related plasma cell neoplasms from the pathology viewpoint. MATERIALS AND METHODS: Current knowledge regarding pathology and genetics of MM is summarized and tissue-based diagnostics following international consensus classifications and the current S3 guideline are described. RESULTS: MM and related neoplasms are composed of malignant plasma cells that secrete a monoclonal immunoglobulin, which is an important parameter of disease activity. MM shows a multistage development. Almost all cases are preceded by a clinically inapparent precursor lesion, monoclonal gammopathy of undetermined significance (MGUS), which can progress to smoldering myeloma with a higher tumor burden, but absence of organ damage. Systemic MM needs to be discerned from the localized forms, solitary osseous and primary extramedullary plasmacytoma. MM is genetically very heterogeneous and can be broadly subdivided into two cytogenetic groups, cases with primary IGH translocations and cases with hyperdiploidy. Intratumoral genetic heterogeneity is frequently pronounced and correlates with the size of focal lesions in imaging. CONCLUSIONS: Diagnosis of plasma cell neoplasms is done according to the criteria of the International Myeloma Working Group (IWMG) and requires interdisciplinary evaluation of clinical, serological, pathological and radiological features. In addition to clinical parameters, molecular markers, especially cytogenetic aberrations, are of great prognostic relevance.

Paediatric chronic myeloid leukaemia presenting in de novo or secondary blast phase - a comparison of clinical and genetic characteristics.

Additional data on blast phase (BP) chronic myeloid leukaemia (CML) in children and adolescents is essential for improving diagnostic and therapeutic approaches of this rare but serious condition. Here, we describe distinct clinical and genetic characteristics of 18 paediatric patients with de novo (n = 10) and secondary (n = 8) BP CML enrolled in the CML-PAED-II trial and registry. Our findings suggest that paediatric patients exhibit a diverse cytogenetic profile compared to adults with BP CML. In addition, patients with de novo BP CML in this cohort presented at a younger age, whereas patients with secondary BP CML more often harboured complex karyotypes.

Biological properties of bone marrow plasma cells influence their recovery in aspirate specimens: impact on classification of plasma cell disorders and potential bias to evaluation of treatment response.

Methods to estimate bone marrow plasma cells (BMPC) basically include histopathology, cytomorphology, and flow cytometry. The present study compares the outcomes of these methods with special focus on the impact of BMPC-specific characteristics on their recovery by either method. Laboratory reports of diagnostic samples from 238 consecutive patients with suspected or known plasma cell disease were retrospectively analyzed. The median (IQR) proportion of BMPC was 30.0% (15.0-70.0%) by histological review (hBMPC), 7.0% (2.0-16.0%) by smear review (sBMPC), and 3.0% (0.8-10.0%) by flow cytometry (fBMPC). The disparity of results between core biopsy and aspirate smear was enhanced in case of poor quality of the smear, increased BM fiber content, higher grade cell atypia, expression of CD56 (all P < 0.0001), the number of cytogenetic aberrations (P = 0.0002), and abnormalities of the MYC gene (P = 0.0002). Conversely, expression of CD19 and a non-clonal plasma cell phenotype were associated with a lower difference between hBMPC and sBMPC (both P < 0.0001). The disparity between the percentages of sBMPC and fBMPC was associated with the quality of the smear (P = 0.0007) and expression of CD56 (P < 0.0001). Our results suggest that the recovery of BMPC in aspirate specimens not only is a matter of sampling quality but also depends on biological cell properties. Aspiration failure due to malignant type features of BMPC may lead to misclassification of plasma cell disorders and represent a bias for the detection of minimal residual disease after therapy.

One-Decade-Spanning transgenerational effects of historic radiation dose in wild populations of bank voles exposed to radioactive contamination following the chernobyl nuclear disaster.

The concept of historic radiation doses associated with accidental radioactive releases and their role in leading to radiation-induced non-targeted effects on affected wild animals are currently being evaluated. Previous research studying Fukushima butterfly, Chernobyl bird and fruit fly populations shows that the effects are transgenerational, underlined by the principles of genomic instability, and varied from one species to another. To further expand on the responses of and their sensitivity in different taxonomically distinct groups, the present study sought to reconstruct historic radiation doses and delineate their effects on bank voles (Clethrionomys glareolus) found within a 400-km radius of the Chernobyl Nuclear Power Plant meltdown site. Historic dose reconstruction from the whole-body dose rates for the bank vole samples for their parental generation at the time of radioactive release was performed. Relationships between the historic doses and cytogenetic aberrations and embryonic lethality were examined via graphical presentations. Results suggest that genomic instability develops at the historic dose range of 20-51 mGy while a radioadaptive response develops at the historic dose range of 51-356 mGy. The Linear No-Threshold (LNT) relationship was absent at historic doses of lower than 356 mGy at all generations. However, LNT was apparent when the very high historic dose of 10.28 Gy in one sampling year was factored into the dose response curve for the bank vole generation 21-22. It is worth being reminded that natural mutation accumulation and other environmental stressors outside the realm of dose effects could contribute to the observed effects in a multiple-stressor environment. Nevertheless, the consistent development of genomic instability and radio-adaptive response across generations and sampling sites unearths the utmost fundamental radiobiological principle of transgenerational non-targeted effects. As a result, it calls for better attention and regulation from global governing bodies of environmental health protection.

Incidence and prognostic impact of cytogenetic aberrations in patients with systemic mastocytosis.

The clinical behavior of systemic mastocytosis (SM) is strongly associated with activating mutations in KIT (D816V in >80% of cases), with the severity of the phenotype influenced by additional somatic mutations, for example, in SRSF2, ASXL1, or RUNX1. Complex molecular profiles are frequently associated with the presence of an associated hematologic neoplasm (AHN) and an unfavorable clinical outcome. However, little is known about the incidence and prognostic impact of cytogenetic aberrations. We analyzed cytogenetic and molecular characteristics of 109 patients (KIT D816V+, n = 102, 94%) with indolent (ISM, n = 26) and advanced SM (n = 83) with (n = 73, 88%) or without AHN. An aberrant karyotype was identified in SM-AHN (16/73, 22%) patients only. In patients with an aberrant karyotype, additional somatic mutations were identified in 12/16 (75%) patients. Seven of 10 (70%) patients with a poor-risk karyotype, for example, monosomy 7 or complex karyotype, and 1/6 (17%) patients with a good-risk karyotype progressed to secondary acute myeloid leukemia (n = 7) or mast cell leukemia (n = 1) within a median of 40 months (range 2-190, P = .04). In advanced SM, the median overall survival (OS) of poor-risk karyotype patients was significantly shorter than in good-risk/normal karyotype patients (4 vs 39 months; hazard ratio 11.7, 95% CI 5.0-27.3; P < .0001). Additionally, the shortened OS in patients with poor-risk karyotype was independent from the mutation status. In summary, a poor-risk karyotype is an independent prognostic variable in advanced SM. Cytogenetic and molecular analyses should be routinely performed in all patients with advanced SM ± AHN because these investigations greatly support prognostication and treatment decisions.

Clinical impact of KMT2C and SPRY4 expression levels in intensively treated younger adult acute myeloid leukemia patients.

OBJECTIVE: To evaluate the prognostic impact of gene expression levels (ELs) of two tumor suppressor genes, sprouty 4 (SPRY4, located on 5q) and lysine methyltransferase 2C (KMT2C, located on 7q) in correlation with clinical characteristics and genetic abnormalities assessed at initial diagnosis in acute myeloid leukemia (AML). METHOD: Gene expression levels were measured on cDNA by RT-qPCR from diagnostic bone marrow samples of 275 intensively treated adult AML patients (median age, 48 years). RESULTS: KMT2C ELs were significantly lower in abn7q/-7 (P = .001), whereas SPRY4 ELs were not associated with abn5q/-5. Higher KMT2C and SPRY4 ELs were significantly associated with lower genetic risk groups as defined by the European LeukemiaNet classification. Additionally, KMT2C ELs were lower in cytogenetically normal patients with DNMT3A (P = .01) or FLT3-ITD mutations (P = .05). KMT2C ELs were not associated with prognosis, whereas higher SPRY4 ELs showed a favorable impact on event-free (EFS, P = .01), relapse-free (RFS, P = .01) and in-trend on overall survival (P = .06) for cytogenetically abnormal patients, which was confirmed in multivariable analysis for EFS (HR, 0.84; 95%-CI, 0.73-0.97; P = .02) and RFS (HR, 0.85; 95%-CI, 0.73-0.98; P = .02). CONCLUSION: Our data indicate that KMT2C ELs are associated with specific genetic features and that SPRY4 ELs may add prognostic information.

Cytogenetic Alterations and Correlation with Age and Gender in Patients of Multiple Myeloma: A Study from a Tertiary Care Center in Eastern India.

Karuna JhaBackground Multiple myeloma is a cytogenetically heterogeneous, evolving, and incurable disease. Differences in prevalence of myeloma already exist in Indian subcontinent as compared with Western world countries. This study attempts to investigate differences in incidence of cytogenetic abnormalities (CA) in Eastern Indian patients and study differences in incidence with respect to age and gender. Materials and Methods Interphase fluorescence in situ hybridization (FISH) was applied on purified plasma cells of 280 newly diagnosed myeloma cases using specific probes. Statistical Analysis Data was analyzed using SPSS software version 25. Results Note that 51.07% patients were FISH positive. Del13q was the most common CA. Significant association of del 13q with t(4;14), del 17p, and gain of 1q was seen. The frequencies of FISH positive and negative groups differed in the different age groups; higher number of cases in 41 to 50 years group in FISH positive group ( p < 0.05) and lower number of cases in FISH positive group in 61 to 70 years ( p < 0.05) as compared with FISH negative group. Del 17p had higher number of cases in age group 41 to 50 years and 51 to 60 years as compared with other age groups. Incidence of t(11;14) was in 5th to 7th decade while del 13q and t(4;14) had the widest range of age at presentation. Gender disparities were seen in high-risk cytogenetics like del 17p and 1q gain. Conclusion The differences in incidence rate of CAs per se in myeloma cases diagnosed in Indian subcontinent and the differences in incidence with respect to age and gender warrant further multicentric studies.

Gene Mutations Associated With Chronic Lymphocytic Leukemia (CLL) Among Saudi CLL Patients and Treatment Outcomes: A Single-Center Experience.

Background Chronic lymphocytic leukemia (CLL) starts in white blood cells in the peripheral blood (stages 0 and 1). In CLL, leukemia cells often build up slowly. Many gene mutations are associated with CLL, such as trisomy 12, 13q14 deletion, and 17q deletion. Due to the lack of patients' disease characteristics, gene mutations, and treatment outcomes data among Saudi patients, this study aimed to identify the relation between the gene mutations of CLL and the treatment in King Abdulaziz Medical City (KAMC), Riyadh. Methods This cross-sectional study used data from the BESTCare hospital information system. The study included all patients diagnosed with CLL and confirmed by flow cytometry in KAMC, Riyadh, between January 2010 and October 2020. The data included demographic information, mutation type or chromosome, present comorbidity, and type of treatment. Results The study included 100 CLL patients. According to different types of clusters of differentiation (CD), CD5 was positive in 84 (84%) patients, and 88 (88%) patients were positive for CD19. Cytogenetic remarkers were tested, revealing that 21 (21%) patients with trisomy 12 and 20 (20%) were positive for 13q14 deletion. Observation of patients' disease status based on the cytogenetic remarkers showed that out of 15 patients with trisomy, 12 (80%) had not progressed and were stable and alive. Out of 20 patients with 13q14 deletion, 16 (80%) were alive and 13 (65%) patients were stable. Conclusion CLL patients in KAMC, Riyadh, displayed trisomy 12, which is characterized by the worst prognosis of disease status, as the most frequently detected cytogenetic aberration followed by 13q deletion. However, most patients were stable and alive.

AML with inv(16)/t(16;16) and high-risk cytogenetic abnormalities: atypical features and unfavorable outcome.

OBJECTIVES: Acute myeloid leukemia (AML) with inv(16)/t(16;16) is among the most frequent AML subtypes. It is recognized by the detection of the CBFB-MYH11 fusion which confers a favorable prognosis, irrespective of the presence of secondary cytogenetic abnormalities. However, the effect of additional genetic anomalies on the behavior of inv(16) AML is debatable. Recent case reports describe an unfavorable prognosis for those patients, characterized by early relapse and death. In this study, we present a series of patients with CBFB-MYH11 fusion and high-risk rearrangements to increase knowledge about this potentially distinct subgroup. METHODS: All cases with inv(16)/ t(16;16) and one or more high risk abnormalities were reviewed at two tertiary healthcare centers between years 2006 and 2020 in terms of demographics, biological and clinical data. RESULTS: Among the total 1447 and 1283 AML cases, the frequency was found to be 0,2% and 0.3%. Clinical data could be retrieved for 5 patients. Detected high-risk abnormalities included TP53 and 5q deletion, complex and monosomal karyotype. The median age was 67 years, with a majority of females (M:F = 1:1.5). Two out of 5 patients presented with therapy related AML, with short latency periods. All patients presented with thrombocytopenia and/or leukocytopenia. Bone marrow aspirates revealed atypical morphology and the detection of rare CBFB-MYH11 fusion transcripts. All 5 patients died, with a short mean overall survival of 5.8 months. DISCUSSION AND CONCLUSION: Our series suggests that the presence of high risk abnormalities confers distinct biological features and poor prognosis to inv(16) AML.

MTHFR rs1801133 polymorphism is associated with increased risk of B-cell precursor lymphoblastic leukaemia with recurrent genetic aberrations of fetal origin.

BACKGROUND: Childhood acute lymphoblastic leukaemia (ALL) is a heterogeneous disease associated with multiple risk factors including genetic susceptibility. Polymorphisms in folate genes have been associated with a protective effect against ALL, although some studies contradict these findings. We aimed to test whether there is an association between the MTHFR rs1801133 variant and the occurrence of B-cell precursor ALL (BCP-ALL) taking in account molecularly distinct subtypes of fetal origin. METHODS: We performed a case-control genotyping study with 2067 samples, 1309 ALL and 758 controls, from children aged ≤ 15 years for MTHFR rs1801133 polymorphism. Risk associations were calculated by odds ratios estimated with unconditional logistic regression, adjusted for frequency-matched ethnic groups. RESULTS: Overall, MTHFR rs1801133 does not impact ALL risk in children with more than 6 years of age. A significant positive association for MTHFR rs1801133 variant was found for ALL with KMT2A-r in the dominant model (adj. OR, 1.48, 95 % CI, 1.01-2.17), while ETV6-RUNX1 and Hyperdiploid subgroups have shown a borderline effect (adj. OR, 1.33, 95 % CI, 0.99-1.78). CONCLUSIONS: The polymorphism MTHFR rs1801133 increased the risk of infant ALL in Brazilian population.

Associations between pretherapeutic body mass index, outcome, and cytogenetic abnormalities in pediatric acute myeloid leukemia.

BACKGROUND: Associations between body mass index (BMI), outcome, and leukemia-related factors in children with acute myeloid leukemia (AML) remain unclear. We investigated associations between pretherapeutic BMI, cytogenetic abnormalities, and outcome in a large multinational cohort of children with AML. METHODS: We included patients, age 2-17 years, diagnosed with de novo AML from the five Nordic countries (2004-2016), Hong Kong (2007-2016), the Netherlands and Belgium (2010-2016), and Canada and USA (1995-2012). BMI standard deviations score for age and sex was calculated and categorized according to the World Health Organization. Cumulative incidence functions, Kaplan-Meier estimator, Cox regression, and logistic regression were used to investigate associations. RESULTS: In total, 867 patients were included. The median age was 10 years (range 2-17 years). At diagnosis, 32 (4%) were underweight, 632 (73%) were healthy weight, 127 (15%) were overweight, and 76 (9%) were obese. There was no difference in relapse risk, treatment-related mortality or overall mortality across BMI groups. The frequency of t(8;21) and inv(16) increased with increasing BMI. For obese patients, the sex, age, and country adjusted odds ratio of having t(8;21) or inv(16) were 1.9 (95% confidence interval (CI) 1.1-3.4) and 2.8 (95% CI 1.3-5.8), respectively, compared to healthy weight patients. CONCLUSIONS: This study did not confirm previous reports of associations between overweight and increased treatment-related or overall mortality in children. Obesity was associated with a higher frequency of t(8;21) and inv(16). AML cytogenetics appear to differ by BMI status.

[Clinical significance of cytogenetic monitoring in chronic myeloid leukemia].

Objective: To analyze the association of cytogenetic abnormalities with the prognosis of chronic myeloid leukemia (CML) patients in tyrosine kinase inhibitors (TKI) era. Methods: Karyotype analysis of chromosome G-banding was carried out in 387 newly diagnosed CML patients by short-term culture of bone marrow cells. The correlation of cytogenetic abnormalities and CML progression was explored in combination with ABL tyrosine point mutations. Result: Of 387 patients with positive BCR-ABL fusion gene assayed by fluorescence in situ hybridization (FISH) technique, 94.1% (364/387) patients were Ph positive and 5.9% (23/387) Ph negative; 320 patients (87.9%) had a translocation t (9;22) (q34;q11) and 5 (1.4%) a variant translocation t (v;22) . Additional cytogenetic aberrations (ACA) at diagnosis were found in 10.7% (39/387) Ph(+) patients, major route ACA in 22 (56.4%) cases and minor route ACA in 15 (38.5%) cases and 2 patients (5.1%) lacked the Y chromosome (-Y) ; 23.4% (71/303) patients occurred ACA during TKI treatment and the most frequent abnormalities were abnormal chromosome numbersd, which were likely associated with high proportion of disease progression (χ(2)=168.21, P<0.001) and ABL tyrosine point mutations (χ(2)=29.04, P<0.001) . Newly diagnosed CML-CP patients with t (9;22) (q34;q11) had a longer event-free survival (EFS) and disease-free survival (DFS) rates than that of patients with ACA (P=0.037; P=0.003) , while the overall survival (OS) had no significant differences (P=0.209) . As for CML-CP patients that occurred ACA during TKI therapy would have a marked low OS, EFS and DFS (all P<0.001) compared with no ACA occurred patients. Survival of advanced patients that occurred ACA were dramatically reduced. Conclusion: ACA often emerged during the disease progress in CML patients, regular and timely detection of chromosomes karyotype and ABL tyrosine point mutations during TKI treatment was important for therapeutic evaluation, progress and prognosis of CML.

Clinical Prognostic Factors in 86 Chinese Patients with Primary Myelodysplastic Syndromes and Trisomy 8: A Single Institution Experience.

PURPOSE: The objective was to determine the characteristics and prognostic factors of 86 Chinese patients with trisomy 8 aberrations and compare the prognostic value of International Prognostic System (IPSS) and Revised IPSS (IPSS-R) in this cohort. MATERIALS AND METHODS: A total of 86 cases diagnosed with primary myelodysplastic syndromes (MDS) with isolated tr8 or with tr8 and other additional cytogenetic aberrations diagnosed and treated at the Union Hospital, Tongji Medical College of Huazhong University of Science and Technology between July 2002 and March 2013 were reviewed. RESULTS: The median survival of the entire group was 23.0 months, and acute myeloid leukemia (AML) developed in 43% (37/86) patients within the follow up time. The univariate analysis revealed that overall survival (OS) was correlated with age, thrombocytopenia, absolute neutrophil count, marrow blasts, cytogenetic status and red blood cell transfusion at diagnosis, and the multivariate analysis revealed that age, marrow blasts, cytogenetic status and transfusion dependence were independent parameters for the OS. The cytogenetic complexity and marrow blasts had the strongest impact on the AML transformation by multivariate analysis. Comparing the two prognostic systems, both two systems could successfully discriminate risk groups for survival. IPSS-R was more refined than IPSS for predicting OS, but had no advantage in predicting the risk of AML development. CONCLUSION: This study confirmed the influence of clinical factors on the prognosis of 86 Chinese MDS patients with trisomy 8. In addition, IPSS-R can further refine prognostic discrimination in the IPSS risk categories.

Prognostic value and efficacy evaluation of novel drugs for cytogenetic aberrations in multiple myeloma: a meta-analysis.

Cytogenetic abnormalities have emerged as the major novel prognostic factors in multiple myeloma (MM) patients. This meta-analysis comprehensively investigates the association between the cytogenetic abnormalities and survival of MM patients. We searched the PubMed, EMBASE, SCOPUS, and Cochrane databases for articles published until February, 2014. Thirty eligible studies involving 10276 patients were included to examine the association of three chromosomal abnormalities, t (4; 14), del (17p), and Amp (1q21), with survival in MM patients. The main outcome measures were progression-free survival (PFS) and overall survival (OS). Individuals with t (4; 14), del (17p), and Amp (1q21) had low OS and PFS. In a subgroup analysis for therapy regimen, lenalidomide- and bortezomib-based therapies increased the PFS of patients with Amp (1q21) (HR=1.50, 95% CI=0.95-2.36, p=0.084) and t (4; 14) (HR=1.38, 95% CI=0.90-2.11, p=0.143). The presence of del (17p) elicited no significant influence on the prognosis of patients under different therapy regimens. Our meta-analysis provides globally quantifiable confirmation of the adverse prognostic value of t (4; 14), del (17p), and Amp (1q21) in OS and PFS for MM patients. Lenalidomide- and bortezomib-based therapies were partly conducive to improve the prognosis of individuals with t (4; 14). Bortezomib-based therapy can partly improve the PFS of patients with Amp (1q21).

A rare case of transformation of childhood myelodysplastic syndrome to acute lymphoblastic leukemia.

Transformation of MDS into ALL during childhood is extremely rare. We report a rare case of an 8-yr-old girl who presented with refractory cytopenia of childhood (RCC) that transformed into ALL only 3 months after the diagnosis of childhood MDS. Although no cytogenetic abnormalities were observed in conventional karyotype and FISH analysis, we found several deletions on chromosomes 5q, 12q, 13q, and 22q. Partial homozygous deletion of the RB1 gene was observed on microarray analysis, with the bone marrow specimen diagnosed as ALL. This is the first case report of transformation of ALL from childhood MDS in Korea. We also compared the clinical, cytological, and cytogenetic features of 4 previously reported childhood MDS cases that transformed into ALL.

FISH Analysis for del6q21 and del17p13 in B-cell Chronic Lymphocytic Leukemia in Iranians.

BACKGROUND: B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in the Western world. Major progress has been made in assessing typical chromosomal abnormalities and recognition of the correlation of these chromosomal abnormalities with laboratory features and clinical course of the disease. The most frequent genomic changes are deletions at 13q14, 11q22-23 and 17p13 and trisomy of chromosome 12. OBJECTIVES: The aim of this study was to investigate the frequency of chromosomal aberrations in B-CLL patients' peripheral blood and/or bone marrow using a molecular cytogenetic method, interphase fluorescence in situ hybridization (I-FISH) and to evaluate the correlation between these genomic changes and clinical findings. PATIENTS AND METHODS: I-FISH analyses were performed on bone marrow and blood samples of 66 B-CLL patients. RESULTS: Deletion of 17p13 was found in 11 (16.6%) and deletion 6q21 was present in 5 (7.5%). Statistical analyses were performed to investigate the correlation of these molecular-cytogenetic findings with family history, Rai staging and CD38 marker. No clear differences in distribution was noted for del17p13 and del6q21 among patients with and without family history, and no direct correlation was noted between these genomic changes and CD38 marker, but the correlation of del17p13 and Rai stage was significant. There was a high frequency of Rai stage II within del17p13 patients. CONCLUSIONS: It was demonstrated that the presence of del6q21 in B-CLL patients indicates poor prognosis and on the contrary, presence of del17p13 points at the good prognostic value of the disease.

Genetic aberrations in multiple myeloma characterized by cIg-FISH: a Brazilian context

Genetic abnormalities are critical prognostic factors for patients diagnosed with multiple myeloma (MM). This retrospective, multicenter study aimed to contribute with the genetic and clinical characterization of MM patients in a country with continental dimensions such as Brazil. Genetic abnormalities were assessed by cIg-fluorescent in situ hybridization (cIg-FISH) in a series of 152 MM patients (median age 55 years, 58.5% men). Overall, genetic abnormalities were detected in 52.7% (80/152) of patients. A 14q32 rearrangement was detected in 33.5% (n=51), including t(11;14), t(4;14) and t(14;16) in 18.4, 14.1, and 1% of cases, respectively. del(13q) was identified in 42.7% (n=65) of patients, of whom 49.2% (32/65) presented a concomitant 14q32 rearrangement. del(17p) had a frequency of 5.2% (n=8). del(13q) was associated with high plasma cell burden (≥50%, P=0.02), and del(17p) with advanced ISS stages (P=0.05) and extramedullary disease (P=0.03). t(4;14) was associated with advanced Durie-Salmon stages (P=0.008), renal insufficiency (P=0.01) and was more common in patients over 60 years old. This study reports similar frequencies of genetic abnormalities to most series worldwide, whereas the t(14;16) and del(17p), two high risk factors for newly diagnosed patients, exhibited lower frequencies. Our results expand the knowledge on the molecular features of MM in Brazil, a country where innovative therapies that could overcome a poor prognosis for some genetic abnormalities are not always available.

Genetic aberrations in childhood acute lymphoblastic leukaemia: application of high-density single nucleotide polymorphism array.

Screening of the entire human genome using high-density single nucleotide polymorphism array (SNPA) has become a powerful technique used in cancer genetics and population genetics studies. The GeneChip® Mapping Array, introduced by Affymetrix, is one SNPA platform utilised for genotyping studies. This GeneChip system allows researchers to gain a comprehensive view of cancer biology on a single platform for the quantification of chromosomal amplifications, deletions, and loss of heterozygosity or for allelic imbalance studies. Importantly, this array analysis has the potential to reveal novel genetic findings involved in the multistep development of cancer. Given the importance of genetic factors in leukaemogenesis and the usefulness of screening the whole genome, SNPA analysis has been utilised in many studies to characterise genetic aberrations in childhood acute lymphoblastic leukaemia.