Prevalence of MDS subtypes in Shanghai, China: a comparison of the World Health Organization and French American British classifications

The prognostic impact of loss of chromosome 7 material detected by fluorescence in situ hybridization (FISH) in myeloid malignancies

BACKGROUND

Monosomy 7 (-7) or deletion in its long arm [del(7q)] is among the most common chromosomal abnormalities in myeloid malignancies. There are prognostic variations between -7 and del(7q) in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

AIM

To describe the clinical characteristics, response to treatment, and survival of patients with primary AML and MDS having -7 or del(7q) detected by fluorescence in situ hybridization (FISH).

PATIENTS AND METHODS

The study was conducted on 53 patients with primary AML and MDS. They were tested for chromosome 7 abnormality using FISH technique.

RESULTS

Thirty-one patients had chromosome 7 abnormality and 22 did not. Lower complete remission and higher death rates were observed in patients with -7 (47.6% and 62%, respectively) when compared to patients with del(7q) (70% and 40%, respectively) with no significant difference (p = 0.218 and 0.101, respectively). The median overall survival (OS) of patients with -7, del(7q) and normal chromosome 7 were 32.0, 43.0 and 50.0 months, respectively, with significant statistical difference (p = 0.001). This difference was evident between patients with -7 and those with normal chromosome 7 (p = 0.001), and less evident between patients with -7 and those with del(7q) (p = 0.021).

CONCLUSION

Chromosome 7 analysis has clear impact on the outcome of myeloid malignancies. The prognostic variations between -7 and del(7q) is attributed to multiple factors. Cases with del(7q) have better outcome than cases with -7. FISH provides a powerful tool for detecting and monitoring patients with chromosome 7 abnormalities.

Shanghai Health Study (2001-2009): What was learned about benzene health effects?

The Shanghai Health Study (SHS) was a large epidemiology study conducted as a joint effort between the University of Colorado and Fudan University in Shanghai, China. The study was funded by members of the American Petroleum Institute between 2001 and 2009 and was designed to evaluate the human health effects associated with benzene exposure. Two arms of the SHS included: an occupational-based molecular epidemiology study and several hospital-based case control studies. Consistent with historical literature, following sufficient exposure to relatively high airborne concentrations and years of exposure, the SHS concluded that exposure to benzene resulted in an increased risk of various blood and bone marrow abnormalities such as benzene poisoning, aplastic anemia (AA), myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML). Non-Hodgkin lymphoma (NHL) was not significantly increased for the exposures examined in this study. Perhaps the most important contribution of the SHS was furthering our understanding of the mechanism of benzene-induced bone marrow toxicity and the importance of identifying the proper subset of MDS relevant to benzene. Investigators found that benzene-exposed workers exhibited bone marrow morphology consistent with an immune-mediated inflammatory response. Contrary to historic reports, no consistent pattern of cytogenetic abnormalities was identified in these workers. Taken together, findings from SHS provided evidence that the mechanism for benzene-induced bone marrow damage was not initiated by chromosome abnormalities. Instead, chronic inflammation, followed by an immune-mediated response, is likely to play a more significant role in benzene-induced disease initiation and progression than previously thought.

Prognostic evaluation of ALIP and CD34 immunostaining in IPSS-R subgroups of myelodysplastic syndromes

In order to evaluate the prognostic value of abnormal localisation of immature precursors (ALIP) and CD34 immunostaining in myelodysplastic syndromes (MDS), bone marrow histopathological features in 187 MDS patients were retrospectively analysed and the prognostic significance of ALIP and CD34 immunostaining on overall survival (OS) and progression to leukaemia-free survival (PFS) in total patients and different Revised-International Prognostic Scoring System (IPSS-R) subgroups were evaluated. In univariate analysis, age ≥60, ALIP, ≥5% CD34+ cells, CD34+ clusters and IPSS-R subgroups were associated with shorter OS (p = 0.027, p < 0.0001, p < 0.0001, p < 0.0001, p < 0.0001, respectively) and PFS (p = 0.029, p = 0.006, p = 0.001, p < 0.0001, p < 0.0001, respectively). Haemoglobin level had a significant impact on OS (p < 0.0001) but not on PFS (p = 0.054). In multivariate analysis, ALIP, haemoglobin level, ≥5% CD34+ cells, CD34+ clusters and IPSS-R subgroups had independent influence on OS (p = 0.012, p < 0.0001, p = 0.010, p < 0.0001, p < 0.0001, respectively), while only CD34+ clusters and IPSS-R subgroups had independent influence on PFS (p < 0.0001, p = 0.016, respectively). In different IPSS-R subgroups, ALIP could maintain its prognostic impact in lower IPSS-R risk subgroups, while ≥5% CD34+ cells and CD34+ clusters had significant prognostic value in both lower and intermediate-higher IPSS-R risk subgroups. Therefore, CD34+ clusters showed more important prognostic impact on survival and progression to leukaemia.

Techniques for detecting chromosomal aberrations in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous hematologic diseases. Chromosomal aberrations are important for the initiation, development, and progression of MDS. Detection of chromosomal abnormalities in MDS is important for categorization, risk stratification, therapeutic selection, and prognosis evaluation of the disease. Recent progress of multiple techniques has brought powerful molecular cytogenetic information to reveal copy number variation, uniparental disomy, and complex chromosomal aberrations in MDS. In this review, we will introduce some common chromosomal aberrations in MDS and their clinical significance. Then we will explain the application, advantages, and limitations of different techniques for detecting chromosomal abnormalities in MDS. The information in this review may be helpful for clinicians to select appropriate methods in patient-related decision making.

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.

MicroRNA-194-5p could serve as a diagnostic and prognostic biomarker in myelodysplastic syndromes

Trisomy 8 and trisomy 1q are the most frequent chromosomal abnormalities in Korean patients with myelodysplastic syndrome (MDS). MicroRNA (miRNA) deregulation is involved in the development of hematological malignancies, including MDS, and cancer-associated genomic regions are known to encode miRNAs. The aim of the present study was to investigate the involvement of miRNAs encoded by chromosomes 8 and 1q in MDS. For this, the expression of nine miRNAs encoded by chromosome 8 (miR-30b-5p, miR-30d-5p, miR-101-3p, miR-124-3p, miR-151a-5p, miR-320a, miR-486-5p, miR-596, and miR-875-5p) and three miRNAs encoded by chromosome 1q (miR-29c-3p, miR-194-5p, and miR-214-3p) was compared between 65 MDS patients and 11 controls. We found a significant upregulation of miR-194-5p (5.1-fold, P=0.002) and miR-320a (2.94-fold, P=0.016) in MDS patients compared with controls. The patients with low miR-194-5p expression showed a significantly decreased overall survival (P=0.049). The areas under the miR-194-5p and miR-320a ROC curves were 0.797 (P=0.002) and 0.729 (P=0.016), respectively. Although these findings need to be validated in a larger patient population, our results indicate that miR-194-5p is a candidate diagnostic biomarker for MDS and that low miR-194-5p expression could be associated with poor overall survival for MDS patients.

Standardized fluorescence in situ hybridization testing based on an appropriate panel of probes more effectively identifies common cytogenetic abnormalities in myelodysplastic syndromes than conventional cytogenetic analysis: a multicenter prospective study of 2302 patients in China

In an attempt to establish the advantages of fluorescence in situ hybridization (FISH) studies over conventional cytogenetic (CC) analysis, a total of 2302 de novo MDS patients from 31 Chinese institutions were prospectively selected in the present study for both CC and standardized FISH analysis for +8, -7/7q-, -5/5q-, 20q- and-Y chromosomal abnormalities. CC analysis was successful in 94.0% of the patients; of these patients, 35.9% of the cases were abnormal. FISH analysis was successful in all 2302 patients and detected at least one type of common cytogenetic abnormality in 42.7% of the cases. The incidences of +8, -7/7q-, -5/5q-, 20q- and-Y chromosomal abnormalities by FISH were 4.1% to 8.7% higher than those by CC. FISH identified abnormalities in 23.6% of the patients exhibiting normal CC results and revealed that 20.7% of the patients with adequate normal metaphases (≥20) had abnormal clones. FISH identified cytogenetic abnormalities in 50.4% of the patients with failed CC analysis. In summary, our multicenter studies emphasised and confirmed the importance of applying standardized FISH testing based on an appropriate panel of probes to detect common cytogenetic abnormalities in Chinese de novo MDS patients, particularly those with normal or failed CC results.

The bone marrow niche, stem cells, and leukemia: impact of drugs, chemicals, and the environment

Hematopoietic stem cells (HSCs) are a unique population of somatic stem cells that can both self-renew for long-term reconstitution of HSCs and differentiate into hematopoietic progenitor cells (HPCs), which in turn give rise, in a hierarchical manner, to the entire myeloid and lymphoid lineages. The differentiation and maturation of these lineages occurs in the bone marrow (BM) niche, a microenvironment that regulates self-renewal, survival, differentiation, and proliferation, with interactions among signaling pathways in the HSCs and the niche required to establish and maintain homeostasis. The accumulation of genetic mutations and cytogenetic abnormalities within cells of the partially differentiated myeloid lineage, particularly as a result of exposure to benzene or cytotoxic anticancer drugs, can give rise to malignancies like acute myeloid leukemia and myelodysplastic syndrome. Better understanding of the mechanisms driving these malignancies and susceptibility factors, both within HPCs and cells within the BM niche, may lead to the development of strategies for prevention of occupational and cancer therapy-induced disease.

Dysplasia features of myelodysplastic syndrome in ethnically Chinese people

OBJECTIVE

It was our aim to study the diagnostic significances of various dysplasia characteristics in myelodysplastic syndrome (MDS).

METHODS

We analyzed 160 cases of primary MDS and a control group including 28 cases of paroxysmal nocturnal hemoglobinuria (PNH), 104 cases of idiopathic thrombocytopenic purpura (ITP), 53 cases of non-severe aplastic anemia (NSAA), 40 cases of megaloblastic anemia and 50 cases of infectious and autoimmune diseases. Peripheral blood smears and bone marrow morphology were reviewed.

RESULTS

There was no significant difference in the occurrence rates of a variety of dysplasias in three lineages among MDS, megaloblastic anemia and PNH; however, changes in qualities and quantities in three lineages between NSAA and MDS were significantly different. ITP and MDS showed statistical differences in multiple changes in myeloid and erythroid cells. Significant differences also existed in multiple changes in erythroid series and megakaryocytes between infectious and autoimmune diseases and MDS. Morphological abnormalities highly related with MDS included multinucleated erythroblasts, ringed sideroblasts, poikilocytosis and gigantocytes, pseudo-Pelger neutrophils, ring-shaped nucleus, and micromegakaryocytes.

CONCLUSIONS

It is difficult to discriminate megaloblastic anemia and PNH from MDS by means of cell morphology. Different dysplasias of MDS have specific diagnostic values.

Review of therapeutic options and the management of patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a poorly understood group of disorders caused by one or more genetic aberrations in the bone marrow-derived cell line responsible for hematopoiesis. Recent advances in genetic medicine have offered new insights into the epigenesis as well as the prognosis of MDS, but have not resulted in new or improved curative treatment options. Bone marrow transplantation, introduced before the advent of genetic medicine, is still the only potential cure. Advances in other medical and pharmaceutical areas have broadened the scope of supportive care and disease-modifying therapies, and treating physicians now have a broad range of disease management options depending on a patient's likely prognosis. There is now clear evidence that appropriate supportive care and therapeutic intervention can improve progression-free and overall survival of MDS patients.

Acute myeloid leukemia following exposure to benzene more closely resembles de novo than therapy related-disease

Benzene (Bz) is widely regarded as a prototype environmental leukemogen and individuals chronically exposed are at risk for myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). It is widely assumed that initiation and pathogenesis of AML following Bz exposure (Bz-AML) is similar or identical to therapy-related AML (t-AML), in which clonal cytogenetic abnormalities, including aneuploidy, are initiating events. However, this assumption is not supported by studies reporting actual disease outcomes together with cytogenetic analyses. Here, using clinically relevant cytogenetic, hematologic, and epidemiological methods, we directly show for 722 consecutive AML cases that the pattern of clonal cytogenetic abnormalities encountered in Bz-exposed cases (n = 78) more closely resembles de novo-AML than t-AML. The prevalence of aneuploidy in Bz-exposed- and de novo-AML cases was identical (23%), and no significant increases in -5/5q- (RR = 0.79) (95% CI: 0.29-2.12) or -7/7q- (RR = 1.27) (95% CI: 0.55-2.92) abnormalities were observed between Bz- vs de novo-AML, respectively. Previous studies have suggested a role for autoimmunity in Bz related MDS including immune mediated inflammatory features and positive responses to immunosuppressive therapy which are indistinguishable from those reported in MDS with low risk of progression to AML. These observations are more consistent with an epigenetic model for initiation of Bz-AML in which altered homeostatic regulation in the bone marrow niche, not direct cytogenetic injury, predominates in the initial development of the leukemic stem cell phenotype, a mechanism biologically distinct from previous models of clonal cytogenetic injury. These findings are important for further understanding the biological basis of AML, particularly in environmental and occupational settings.

A case-control study of chronic myelomonocytic leukemia (CMML) in Shanghai, China: evaluation of risk factors for CMML, with special focus on benzene

The authors report the results of a hospital-based case-control study of all patients diagnosed with chronic myelomonocytic leukemia (CMML) (n = 36) from 28 participating hospitals over a 4-year period. Diagnoses were made by a single laboratory using 2001 World Health Organization (WHO) criteria. Subjects were matched to 2 control patients and interviewed concerning previous diseases, work histories, and exposures to potential etiologic agents. Peripheral blood and bone marrow findings revealed clinical features of both myelodysplastic syndromes (MDSs) and myeloproliferative neoplasms (MPNs), consistent with hematopoietic disease category of MDS/MPN. The frequency of clonal cytogenetic abnormalities in all CMML cases was 31%, with no consistent pattern identified. A select number of risk factors associated with occupational exposure, nonoccupational exposure, and prior medical or family history of disease were extracted from the questionnaire. The results were compared between the case and control subjects. A total of 5 study subjects (2 CMML cases and 3 control subjects) were determined to have had some benzene exposure. In addition, none of the highlighted risk factors associated with nonoccupational exposure to etiologic agents was significantly different among the study subjects. These results do not support an increased risk for developing CMML associated with historical exposures to benzene.

Partial and total monosomal karyotypes in myelodysplastic syndromes: comparative prognostic relevance among 421 patients

Myelodysplastic syndromes (MDS) include a group of heterogeneous hematological disorders with a variable risk of leukemic evolution and short survival. Around 40-50% of patients show abnormal karyotypes that are mostly characterized by monosomies or deletions. Cytogenetic findings are an independent prognostic factor and the International prognostic scoring system (IPSS) differentiates three cytogenetic categories, despite the Intermediate one being heterogeneous. The aim of this study, including 421 Argentinean patients with primary MDS, is to characterize the cytogenetic profile, to test its prognostic value and to compare partial and monosomal karyotypes against other cytogenetic findings. An abnormal karyotype (median survival: 26 months) was observed in 176 patients. The presence of complex karyotypes, number of alterations, and the IPSS cytogenetic groups showed significant differences for predicting outcome. Behavior of patients with isolated deletions (median survival: 49 months) did not differ from those with normal karyotype (56 months, P = 0.654) or Good prognostic findings (43 months, P = 0.371). However, a worse prognosis was observed when another alteration was added (31 months, P = 0.043). Karyotypes with autosomal monosomies (median survival: 16 months) had a prognostic impact similar to other Poor cytogenetic findings (17 months, P = 0.626). In our population classified according to French-American-British (FAB) or World Health Organization (WHO), this new categorization of cytogenetic abnormalities, recognizing three different risk groups, showed an independent prognostic impact and a better discriminating power than the IPSS categories. It can be concluded that all isolate deletions (excluding 7q-) are good prognostic findings and all monosomies (excluding Y chromosome loss) are bad indicators.

Cytogenetic features of 5q deletion and 5q- syndrome in myelodysplastic syndrome in Korea; marker chromosomes proved to be chromosome 5 with interstitial deletion by fluorescence in situ hybridization

We characterized the cytogenetic changes and prognostic characteristics of 133 Korean patients with myelodysplastic syndrome (MDS), focusing on 5q- syndrome and MDS with chromosome abnormalities involving 5q deletion according to World Health Organization 2008 classification. In all patients, G banding and fluorescence in situ hybridization for 5q were performed, and in MDS patients with 5q deletion, the deleted region on chromosome 5 was mapped with fluorescence in situ hybridization for EGR1, CSF1R, and PDGFRB. The frequency of isolated del(5q) syndrome and 5q deletion was 2.2% (3 of 137 patients) and 15.3% (21 of 137 patients), respectively. International Prognostic Scoring System (IPSS) groups were low risk (5.8%), intermediate 1 (51.1%), intermediate 2 (27.8%), and high risk (15.3%). The patients with del(5q) were significantly older (62 years) and showed an unfavorable survival compared to patients without del(5q). Half (53%) of the patients with del(5q) also had complex chromosome abnormalities, including chromosome 7 abnormalities. Of the patients with del(5q), 93.3% were deleted for all three regions on 5q, compared to 66.7% of patients with isolated del(5q). Marker chromosomes proved to be chromosome 5 with interstitial deletion of q arm by fluorescence in situ hybridization in three patients. The biological characteristics of MDS in Korea seem to be markedly different from those of Caucasians, with Koreans having a younger age, lower frequencies of 5q- syndrome, higher frequencies of complex cytogenetic abnormalities including del(5q), and poorer prognosis. We infer that additional chromosome abnormalities contribute to the adverse prognostic impact in patients with del(5q).

Integrating WHO 2001-2008 criteria for the diagnosis of Myelodysplastic Syndrome (MDS): a case-case analysis of benzene exposure

We characterized the prevalence of hematopoietic and lymphoid disease for 2923 consecutive patients presenting at 29 hospitals from August 2003 to June 2007. Diagnoses were made in our laboratory using WHO criteria based on morphologic, immunophenotypic, cytogenetic, FISH and molecular data. A total of 611 subjects (322 males/289 females) were prospectively diagnosed with MDS using WHO (2001) criteria. Update and re-evaluation of cases using MDS (2008) criteria resulted in 649 MDS cases. Using WHO (2008) criteria, refractory cytopenia with multilineage dysplasia (RCMD) accounted for 68% of total cases, refractory anemia with excess blasts (RAEB), 16.3%; refractory anemia (RA), 6.5%; refractory cytopenia with unilineage dysplasia (RCUD), 4%; and MDS-unclassifiable (MDS-U), 4.5%. Subjects were administered questionnaires and information on previous disease, work histories and exposures to potential etiologic agents such as benzene (BZ) was obtained. A total of 80/649 (13.2%) were determined to have some BZ exposure. The frequency of clonal cytogenetic abnormalities in all MDS was 30%, the most common being +8>del(20)q>del(7q)>del(5q), while the analogous frequency in BZ-exposed cases was only 24%. To further investigate the characteristics of MDS associated with BZ, we identified a subset of cases with high BZ exposure. These BZ signal cases were each matched by age and gender to two cases with no known BZ exposure. When contrasting BZ signal cases vs matched cases with no BZ exposure, we found a high odds ratio (OR) for the WHO subtype MDS-U (OR=11.1), followed by RAEB and RCUD (OR=1), RA (OR=0.7) and RCMD (OR=0.6). Multilineage dysplasia with abnormal eosinophils (MDS-Eo) was strongly associated with BZ exposure, whereas the relative risk of clonal cytogenetic abnormalities was reduced for high BZ-exposed cases (OR=0.5). These findings are strongly indicative that MDS subtypes are influenced by BZ exposure, and taken together with previous studies, the features of MDS-Eo suggest that altered immune regulation plays a major role in the pathogenesis of MDS following chronic exposure to BZ.

Bone marrow blasts level predicts prognosis in patients with refractory cytopenia with multilineage dysplasia

OBJECTIVES

Current prognostic models for myelodysplastic syndrome (MDS) do not consider the prognostic value of a bone marrow blast level that is <5%. Exploring the prognostic value of the International Prognostic Scoring System (IPSS) and a marrow blast level that is <5% may lead to better risk-adapted therapeutic strategies.

METHODS

According to the World Health Organization classification, most of our patients (65.5%) fell into the new category 'refractory cytopenia with multilineage dysplasia' (RCMD). We evaluated the prognostic value of the IPSS in 435 adult patients with de novo MDS and in the 285 of them that had RCMD in a Chinese population. We also analyzed the prognostic value of bone marrow blast levels in patients with RCMD and in different IPSS risk groups.

RESULTS

We found a significant difference in survival times between RCMD patients with a marrow blast level of 3.5% or higher vs. those with a blast level of <3.5%, with median survival times of 23.7 and 40.8 months, respectively. In addition, application of a marrow blast level cutoff of 3.5% in patients with RCMD could identify patients with a lower IPSS risk but with a potentially worse prognosis. Multivariate analysis showed marrow blast level (using 3.5% as the cutoff) to be an independent factor that impacted survival times of patients with RCMD. Furthermore, we also found that IPSS had strong prognostic value in Chinese RCMD population.

CONCLUSION

In patients with RCMD, a higher percentage of marrow blasts was associated with a worse prognosis.

Prospective analysis of clinical and cytogenetic features of 435 cases of MDS diagnosed using the WHO (2001) classification: a prognostic scoring system for predicting survival in RCMD

We characterized the prevalence, clinical and cytogenetic characteristics and survival of 435 patients diagnosed with de novo MDS in a single laboratory according to WHO criteria, and compared the utility of different scoring systems to predict survival for individual subtypes of MDS. The mean follow-up period was 25.1 (5.5-53.2) months. Our results confirm major differences in the age-distribution and prevalence of individual subtypes of MDS between Asian and Western patients with a median age of 58 years and a predominance of RCMD (69.9%). Survival rates were similar to those reported in the West: the 3-year survival rate for MDS was 46.7% with a median survival time for RCMD of 38 months and RAEB, 10 months. We found that the IPSS and WPSS scoring systems, which are weighted heavily by blast cell count and karyotype, were not independent predictors for survival in RCMD patients. Multivariate analysis demonstrated that a scoring system based on age (> or =60 years), ANC (<1.0 x 10(9)/L), Hb (<90 g/L), number of cytopenias and complex karyotype is a more useful predictor of survival in RCMD.

The TNF-alpha 238A polymorphism is associated with susceptibility to persistent bone marrow dysplasia following chronic exposure to benzene

Chronic exposure to benzene can result in transient hematotoxicity (benzene poisoning, BP) or persistent bone marrow pathology including dysplasia and/or acute myeloid leukemia. We recently described a persistent bone marrow dysplasia with unique dysplastic and inflammatory features developing in individuals previously exposed to benzene (BID) [Irons RD, Lv L, Gross SA, Ye X, Bao L, Wang XQ, et al. Chronic exposure to benzene results in a unique form of dysplasia. Leuk Res 2005;29:1371-80]. In this study we investigated the association of single nucleotide polymorphisms (SNP) (-863 (C-->A), -857 (C-->T), -308 (G-->A), -238 (G-->A)) in the promoter region of the cytokine, tumor necrosis factor-alpha (TNF-alpha) on the development of BP, persistent BID and de novo myelodysplastic syndrome (MDS) in 394 individuals. Only the -238 (G-->A) polymorphism was significantly associated with the development of BID (odds ratio (OR)=7.4; 95% C.I. 1.23-44.7) and was specific for BID and not de novo MDS or BP. These findings are consistent with a role for inflammation in the development of BID and suggest that cell-specific alterations in TNF-alpha expression may promote clonal selection in the evolution of neoplastic hematopoietic disease.