Incidence of common chimeric fusion transcripts in B-cell acute lymphoblastic leukemia: an Indian perspective

A surrogate molecular approach for the detection of Philadelphia chromosome-like B-acute lymphoblastic leukemia

BACKGROUND

Philadelphia chromosome (Ph)-like B-acute lymphoblastic leukemia (B-ALL) is a clinically significant, high-risk genetic subtype of B-ALL cases. There are few data on the incidence, characterization, and treatment outcomes of Ph-like ALL cases from low- and middle-income countries. There is a pressing need to establish a well-organized/cost-effective approach for identifying Ph-like ALL instances.

METHODS

Multiplex reverse transcriptase polymerase chain reaction, nCounter NanoString, and fluorescence in situ hybridization were used to detect and characterize Ph-like ALL cases among recurrent genetic abnormalities (RGA)neg B-ALL cases. At the end of induction therapy, flow cytometry-minimal residual disease (MRD) assay was used to quantify MRD positivity in Ph-like ALL cases.

RESULTS

Of 130 newly diagnosed B-ALL cases, 25% (BCR::ABL1), 4% (ETV6::RUNX1), 5% (TCF3::PBX1), 2% (KM2TA::AFF1), and 65% RGAneg B-ALL cases were revealed by multiplex reverse transcriptase polymerase chain reaction. Among RGAneg B-ALL cases, 24% Ph-like ALL cases using nCounter NanoString were identified, with 48% CRLF2high cases with 45% CRLF2::P2RY8 and 18% CRLF2::IGH rearrangements(∼r) revealed by fluorescence in situ hybridization. In 52% of CRLF2low cases, 17% ABL1 and JAK2∼r 8% EPOR::IGH & PDGRFB∼r were identified. Ph-like ALL cases had higher total leukocyte count (p < .05), male preponderance (p < .05), and high MRD-positivity/induction failure compared with RGAneg B-ALL cases. Furthermore, in Ph-like ALL cases, 11 significant genes using quantitative polymerase chain reaction were identified and validated. CRLF2, IGJ, CEACAM6, MUC4, SPATS2L and NRXN3 genes were overexpressed and show statistical significance (p < .05) in Ph-like ALL cases.

CONCLUSIONS

This study showed the high incidence of Ph-like ALL cases with kinase activating alterations and treatment outcomes from low- and middle-income region. Furthermore, a surrogate cost-effective multiplex panel of 11 overexpressed genes for the prompt detection of Ph-like ALL cases is proposed.

PLAIN LANGUAGE SUMMARY

Identification of recurrent gene abnormalities (RGA)neg B-acute lymphoblastic leukemia (B-ALL) cases using multiplex-reverse transcriptase polymerase chain reaction. Identification and characterization of Philadelphia (Ph)-like ALL cases using nCounter NanoString gene expression profiling and fluorescence in situ hybridization. Furthermore, Ph-like ALL cases were characterized according to CRLF2 expression and kinase-activating genomic alterations. Minimal residual disease of Ph-like ALL cases were quantified using flow cytometry-minimal residual disease assay. A surrogate molecular approach was established to detect Ph-like ALL cases from low- and middle-income countries.

Identification and validation of the optimal reference genes for standardizing the gene expression profiling diagnostic panel of Ph-like B-lineage acute lymphoblastic leukemia

Gene expression profiling is the criterion standard for recognizing Ph-like ALL signatures among B-ALLs. The prerequisite of GEP is the accurate normalization of target genes with stable expression of housekeeping genes in a quantitative PCR. HKGs exhibit differential expression in the different experimental conditions and affect the target genes' expression, leading to imprecise qPCR results. The selection of stable HKGs is crucial in GEP experiments, especially in identifying high-risk Ph-like ALL cases. We have evaluated the expression stability of nine HKGs (GAPDH, ACTB, GUSB, RNA18S, EEF2, PGK1, B2M, TBP and ABL1) in identified Ph-like ALLs and Ph-negative (n = 23 each) using six algorithms, 4 traditional softwares; geNorm, BestKeeper, NormFinder, Delta Cq value method, and two algorithms, RefFinderTM and ComprFinder. Further, we have validated the expression of 8 overexpressed normalized genes in Ph-like ALL cases (JCHAIN, CA6, MUC4, SPATS2L, BMPR1B, CRLF2, ADGRF1 and NRXN3). GeNorm, BestKeeper, NormFinder, Delta Cq value method, RefFinderTM and ComprFinder algorithm analysis revealed that EEF2, GAPDH, and PGK1 form the best representative HKGs in Ph-like ALL cases, while RNA18s, ß-actin, and ABL1 in Ph-negative ALLs. Lastly, we performed a correlation analysis and found that the combination of EEF2, GAPDH, and PGK1 represents the best combination with a very high correlation in Ph-like ALL cases. This is the first report that shows EEF2, GAPDH, and PGK1 are the best HKG genes and can be used in the diagnostic panel of Ph-like ALL cases using qPCR at baseline diagnosis.

Hematological, clinical, immunophenotypic characterization, and treatment outcomes of prognostically significant genetic subtypes of B-lineage acute lymphoblastic leukemia: A report of 1021 patients from India

BACKGROUND

The published literature on hematological, clinical, flowcytometric-immunophenotyping, and minimal residual disease outcomes of the prognostically important genetic subtypes of acute lymphoblastic leukemia (ALL) is scarce from low-income countries. For newer classifications such as BCR::ABL1-like ALLs, the scarcity of patient-level data is even more pronounced.

METHODS

The authors performed comprehensive detection of recurrent gene fusions and BCR::ABL1-like ALL cases followed by immunophenotypic profiling and obtained clinical outcome parameters for a large cohort (n = 1021) of patients from India. This cohort included a significant number of patients with BCR::ABL1-like ALL subtype and other genetic subtypes of ALL.

RESULTS

Patients with BCR::ABL1-positive and BCR::ABL1-like ALL were significantly older, had male preponderance, and expressed a higher white blood cell count than BCR::ABL1-negative cases (p < .05). Logistic regression modeling of B-lineage-ALL (B-ALL) subtypes revealed that cluster of differentiation (CD)36 is a strong statistically significant predictive marker of BCR::ABL1-like ALL (p < .05). Furthermore, patients with BCR::ABL1-like ALLs show a significantly higher frequency of CD36 expression compared to BCR::ABL1-negative ALLs (p < .05). In terms of clinical symptoms, lymphadenopathy is a strong statistically significant predictive marker in BCR::ABL1-like ALLs compared to BCR::ABL1-negative ALL cases (p < .05). In terms of treatment outcomes, minimal residual disease (MRD) positivity in BCR::ABL1-positive ALL cases were statistically significant (p < .05), and BCR::ABL1-like ALL cases had high MRD-positivity as compared to BCR::ABL1-negative ALL cases but did not show statistical significance.

CONCLUSIONS

The findings evince the use of novel therapies and personalized treatment regimens to improve the overall survival of the newer incorporated entities in B-ALLs. This is the first report characterizing the hematological, clinical, flowcytometric-immunophenotyping, and minimal residual disease outcomes of the prognostically significant subtypes of ALLs in patients from India.

PLAIN LANGUAGE SUMMARY

Characterizing the hematological, clinical, flowcytometric-immunophenotyping, and minimal residual disease outcomes of the prognostically significant subtypes (n = 1021) of acute lymphoblastic leukemia (ALLs) in patients from India. We have made two independent logistic regression models of cluster of differentiation (CD) markers and clinical symptoms to differentiate prognostically significant subtypes of ALLs. Logistic regression analysis of CD markers revealed CD36 as a strong predictor in BCR::ABL1-like ALL cases compared to BCR::ABL1-negative ALL cases. Logistic regression analysis of clinical symptoms revealed lymphadenopathy significantly predicts BCR::ABL1-like ALLs (p < .05). In terms of treatment outcomes, BCR::ABL1-positive ALL had statistically significant minimal residual disease (MRD) (p < .05), and BCR::ABL1-like ALL cases had high MRD-positivity but did not show statistical significance as compared to BCR::ABL1-negative ALLs.

'Evaluation of adverse prognostic gene alterations & MRD positivity in BCR::ABL1-like B-lineage acute lymphoblastic leukaemia patients, in a resource-constrained setting

BACKGROUND

Early detection of BCR::ABL1-like ALL could impact treatment management and improve the overall survival/outcome. BCR::ABL1-like ALL cases are characterised by diverse genetic alterations activating cytokine receptors and kinase signalling. Its detection is still an unmet need in low-middle-income countries due to the unavailability of a patented TLDA assay.

METHODS

This study's rationale is to identify BCR::ABL1-like ALLs using the PHi-RACE classifier, followed by the characterisation of underlying adverse genetic alterations in recurrent gene abnormalities negative (RGAneg) B-ALLs (n = 108).

RESULTS

We identified 34.25% (37/108) BCR::ABL1-like ALLs using PHi-RACE classifier, characterised by TSLPR/CRLF2 expression (11.58%), IKZF1 (Δ4-7) deletion (18.9%) and chimeric gene fusions (34.61%). In overexpressed TSLPR/CRLF2 BCR::ABL1-like ALLs, we identified 33.33% (1/3) CRLF2::IGH and 33.33% (1/3) EPOR::IGH rearrangements with concomitant JAK2 mutation R683S (50%). We identified 18.91% CD13 (P = 0.02) and 27.02% CD33 (P = 0.05) aberrant myeloid markers positivity, which was significantly higher in BCR::ABL1-like ALLs compared to non-BCR::ABL1-like ALLs. MRD positivity was considerably higher (40% in BCR::ABL1-like vs. 19.29% in non-BCR::ABL1-like ALLs).

CONCLUSIONS

With this practical approach, we reported a high incidence of BCR::ABL1-like ALLs, and a lower frequency of CRLF2 alteration & associated CGFs. Recognising this entity, early at diagnosis is crucial to optimise personalised treatment strategies.

Genomic and proteomic characterization of Philadelphia-like B-lineage acute lymphoblastic leukemia: A report of Indian patients

BACKGROUND

The gold standard for the identification of Philadelphia (Ph)-like acute lymphoblastic leukemia (ALL) patients is gene expression profiling. Because of its diverse nature, its identification is extremely difficult and expensive. On the genomic and proteomic landscape of Ph-like ALL patients, there is a paucity of published literature from developing countries.

METHODS

The authors used digital barcoded nCounter NanoString gene expression profiling for its detection, followed by molecular and proteomic characterization using fluorescence in situ hybridization and liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

The authors found 32.05% Ph-like ALL patients and their median age at presentation was considerably higher than Ph-negative ALL cases (p = .0306). Furthermore, we identified 20% CRLF2 overexpressed cases having 8.33% CRLF2-IGH translocation with concomitant R683S mutation and 8.33% CRLF2-P2RY8 translocation. In 80% of CRLF2 downregulated cases, we identified 10% as having JAK2 rearrangement. Minimal residual disease-positivity was more common in Ph-like ALL cases (55.55% vs. 25% in Ph-negative ALL cases). Immunoglobulin J chain (Jchain), small nuclear ribonucleoprotein SmD1 (SNRPD1), immunoglobulin κ constant (IGKC), NADH dehydrogenase (ubiquinone) 1 α subcomplex subunit 2 (NDUFA2), histone H2AX (H2AFX), charged multivesicular body protein 4b (CHMP4B), and carbonyl reductase (NADPH) (CBR1) proteins were identified to be substantially expressed in Ph-like ALL patients, using LC-MS/MS. Gene enrichment analysis indicated that involvement of spliceosomal mediated messenger RNA splicing pathway and four microRNAs was statistically significant in Ph-like ALL patients.

CONCLUSIONS

For the first time, we have described incidence, molecular, and proteomic characterization of Ph-like ALL, in developing nations.

PLAIN LANGUAGE SUMMARY

In developing countries, detecting Philadelphia (Ph)-like B-lineage acute lymphoblastic leukemia is complicated and challenging due to its diverse genetic landscape. There is no well-defined and cost-effective methodology for its detection. The incidence of this high-risk subtype is very high in adult cases, and there is an urgent need for its accurate detection. We have developed an online PHi-RACE classifier for its rapid detection, followed by delineating the genomic and proteomic landscape of Ph-like acute lymphoblastic leukemias for the first time in Indian patients.

Cytogenetics and Molecular Genetics in Pediatric Acute Lymphoblastic Leukemia (ALL) and Its Correlation with Induction Outcomes

Arathi SrinivasanAims  The aim was to study cytogenetics and molecular genetic profile in pediatric B-acute lymphoblastic leukemia (ALL) and correlate it with induction outcomes. Subjects and Methods  A retrospective study of cytogenetics and molecular genetics of 98 children with B-cell ALL from January 2013 to May 2018 was done. Cytogenetics and molecular genetics were done in the bone marrow using multiplex reverse transcription polymerase chain reaction and G-banded karyotyping, respectively. Minimal residual disease (MRD) assessment was done at the end of induction by flowcytometry. Results  Of the 98 children, 83 (84.6%) had evaluable cytogenetics, with 11 (13.25%) being abnormal karyotypes. Of the 11 abnormal karyotypes, seven children (8.4%) had hyperdiploidy, one had hypodiploidy, and three had miscellaneous findings. In molecular genetics, TEL-AML1 (ETV6/RUNX1)[t(12;21)] was the most common fusion gene abnormality (12.2% [12/98]), followed by E2A-PBX1 [t(1;19)] (5%), BCR/ABL1 [t(9;22)] (3%), and MLL-AF4 [t(4;11)] (1%). All the 98 children attained morphologic remission at the end of induction. All children with hyperdiploidy (7/7) attained remission and MRD negativity, but one expired during maintenance chemotherapy of disseminated tuberculosis. The child with hypodiploidy was MRD-positive. Three (25%) children with t (12;21) were MRD-positive. All children with Ph + ALL, t(1:19), and t(4;11) were MRD-negative. Fifty-two children had no detected abnormalities, six of whom had MRD positivity (11.5%). Conclusion  Cytogenetic and molecular genetic subgrouping prognosticates ALL outcomes. Although 25% of TEL-AML + children had MRD positivity, larger studies are required to validate the same. End-of-induction MRD outcomes did not correlate with chromosomal aberrations.

Retrospective Study of B Lymphoblastic Leukemia to Assess the Prevalence of TEL/AML1 in South India: A Study of 214 Cases and Review of Literature

Introduction Translocation t(12;21)(p13;q22), a recurrent and an invisible chromosomal abnormality, resulting in TEL/AML1 gene fusion, associated with good prognosis, has been described to be a common abnormality, in children with B-acute lymphoblastic leukemia (B-ALL).

Objectives The initial observation of very few TEL/AML1 positive patients at this center on testing by fluorescence in situ hybridization (FISH) led to study the prevalence of the abnormality, compare with the global distribution, and evaluate clinical, pathological, molecular, and cytogenetic features in TEL/AML1 positive patients.

Materials and Methods A retrospective study of all B-ALL patients tested for TEL/AML1 gene fusion during the period January 2009 to November 2020 was undertaken. Clinicopathological, molecular, cytogenetic, treatment, and follow-up details were collected. All publications dealing with TEL/AML1 gene rearrangement were reviewed post Google and PubMed search.

Results TEL/AML1gene rearrangement was assessed by FISH in 178 patients and by reverse transcription polymerase chain reaction in 36 patients and detected as the sole abnormality in 8.4% patients with additional genetic abnormalities noted on FISH evaluation. Normal karyotype was noted in 14/18 (77.7%) of these patients and 2 had complex karyotype. Complete blood count revealed hemoglobin to range from 35 to 116 g/L (median: 74 g/L), white blood count: 1.01–110×109/L (median: 7.8×109/L), platelet counts: 10–115×109/L (median: 42×109/L), blast count in peripheral smear: 0–98% (median: 41%). Immunophenotyping demonstrated 94.4% were CD34 positive, common acute lymphoblastic leukemia associated antigen (CALLA) positive with aberrant expression of CD13, CD33, CD56, singly or in combination in 58.8%.

Conclusion TEL/AML1 fusion is rare in Indian patients with B-ALL and appears to be much rarer in our region. The detection of relevant specific abnormalities is of fundamental importance in B-ALL patients and these geographic variations can be used in defining management policies.

Identification and validation of suitable housekeeping genes for gene expression studies in BCR-ABL1 positive B-lineage acute lymphoblastic leukemia

BACKGROUND

The stability of the housekeeping gene (HKG) expression is an absolute prerequisite for accurate normalization of target gene expression in a quantitative real-time polymerase chain reaction (RQ-PCR). In RQ-PCR, the widely used normalization approach involves the standardization of target genes to the most stable HKG control genes. According to the recent literature, in different experimental conditions the HKGs exhibit either up or down-regulation and thus affecting the gene expression profiles of target genes which leads to erroneous results. This implies that it is very important to select the appropriate HKG and verify the expression stability of the HKG before quantification of the target gene.

METHODS AND RESULTS

The present study aims to analyze six different HKGs for their expression profiles and stability in BCR-ABL1 negative cases and validate them in BCR-ABL1 positive cases, detected by multiplex reverse transcribed polymerase chain reaction (RT-PCR). Six commonly used reference genes (GAPDH, ABL1, RNA18S, ACTB, GUSB, and EEF2) were selected in this study. RQ-PCR was performed on 24 BCR-ABL1 negative cases and the outcomes were validated on 24 BCR-ABL1 positive cases. RefFinder™, a web-based composite software was used to check the stability of HKG genes by different algorithms and comprehensive ranking of each HKG gene in BCR-ABL1 negative cases and finally validated in BCR-ABL1 positive cases.

CONCLUSIONS

It was found that RNA18S, ABL1 and GUSB are good stable HKG genes, which showed minimum variability in gene expression compared to GAPDH, EEF2, and ACTB, the most commonly used HKG.

Characterization of the immunophenotypic aberrancies with respect to common fusion transcripts in B-cell precursor acute lymphoblastic leukaemia - a report of 986 Indian patients

Objective:

Based on the immunophenotype, acute lymphoblastic leukemia (ALL) can be categorized into B-cell or T-cell lineages. B-cell precursor ALL (BCP-ALL) cases show various genetic/molecular abnormalities, and varying frequencies of chimeric fusion transcripts in BCP-ALL cases are reported from different parts of the world. We studied the immunophenotypic aberrancy profiles of a large number of BCP-ALL cases with respect to various common chimeric fusion transcripts.

Materials and Methods:

Flow cytometric immunophenotyping and multiplex reverse-transcription polymerase chain reaction assays were performed for 986 BCP-ALL cases.

Results:

Among 986 BCP-ALL cases, the incidence of various fusion transcripts was 38.36% in adult cases and 20.68% in pediatric cases. Adult BCP-ALL patients with t(9;22)(BCR-ABL1) fusion transcripts and expression of aberrant myeloid markers were significantly older at presentation (p=0.0218) with male preponderance (p=0.0246) compared to those without aberrant myeloid expression. In pediatric patients with the t(12;21)(ETV6-RUNX1) chimeric fusion transcript, aberrant expression of CD13 was observed in 39.13%, CD33 in 36.95%, and CD117 in 8.69% of patients, respectively. Pediatric BCP-ALL patients with the ETV6-RUNX1 fusion transcript and expression of aberrant myeloid markers were not significantly different compared to those without with respect to demographic and clinical/hematological characteristics (p=0.5955). Aberrant myeloid markers were rarely or never expressed in pediatric and adult BCP-ALL patients with the t(4;11)(KTM2A-AF4) and t(1;19)(TCF3-PBX1) fusion transcripts.

Conclusion:

Aberrant myeloid markers were frequently expressed among BCP-ALL patients with the t(9;22)(BCR-ABL1) and t(12;21)(ETV6-RUNX1) fusion transcripts. However, BCP-ALL patients with the t(4;11)(KTM2A-AF4) and t(1;19)(TCF3-PBX1) fusion transcripts rarely or never expressed aberrant myeloid markers. Aberrant myeloid CD markers can be used in predicting chimeric fusion transcripts at baseline so as to plan appropriate tyrosine kinase inhibitor therapy in cases of BCP-ALL with specific chimeric fusion transcripts. This study has delineated the relationship of chimeric fusion transcripts with the aberrant expression of myeloid markers in a large cohort of BCP-ALL cases.

An Evaluation of a Fluorescence In Situ Hybridization Strategy Using Air-dried Blood and Bone-marrow Smears in the Risk Stratification of Pediatric B-Lineage Acute Lymphoblastic Leukemia in Resource-limited Settings

Cytogenetic abnormalities (CAs), one of the strongest influencers of therapeutic outcome in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL), can be identified by different techniques. Despite several technological advances, many centers with resource-limited settings continue to use either reverse-transcriptase polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH) to identify prognostically relevant CAs. We evaluated a simple and cost-effective triple-probe FISH strategy on air-dried blood and bone-marrow smears and compared its performance with a multiplex RT-PCR-based approach in the prognostication of pediatric BCP-ALL patients. Three hundred twenty BCP-ALL patients were tested prospectively and in parallel by FISH on air-dried blood or bone-marrow smears and RT-PCR. The FISH strategy correctly diagnosed all genetic abnormalities identified by RT-PCR. Prognostically relevant genetic abnormalities were missed by RT-PCR in 24 (8.1%) patients. In another 20 children (6%), with samples inadequate for RT-PCR testing (dry taps or due to poor sample quality), a successful FISH testing could be performed on bone-marrow aspirate or trephine-imprint smears. In addition, FISH detected ploidy changes, which could be confirmed by FxCycle Violet-based flow-cytometry. FISH testing on air-dried smears identified more prognostically relevant CAs, provided information on the ploidy status, and could be successfully performed in children with difficulty in bone-marrow sampling.

Low spontaneous apoptosis index at diagnosis predicts a high-risk phenotype in paediatric acute lymphoblastic leukaemia

Background & objectives:

Significance of apoptosis as a prognostic marker is less well studied in paediatric acute lymphoblastic leukaemia (ALL) cases. Hence, a prospective study, involving 30 paediatric ALL cases, was done to assess the clinical relevance of in vivo apoptosis.

Methods:

Peripheral blood mononuclear cells from all patients were subjected to annexin V/propidium iodide staining to detect the degree of apoptosis [apoptotic index (AI)] at day 0 and day 35 post-induction chemotherapy. In addition, Bax and Bcl2 apoptotic protein expressions were studied at day 0 and their relative fluorescence mean intensity (RFMI) ratios were calculated.

Results:

Mean age of patients was 5.1 years. Of the 30 cases, 21 (70%) were at standard-risk, five (17%) at intermediate and four (13%) at high risk. Majority (83%) were B-ALL. Day 8 absolute blast count was >1000/μl in seven (23%) and <1000/μl in 23 of 30 (77%) cases. Day 35 marrow was M1 in 23 (92%) and M2 in two of 25 (8%) cases. AI at day 0 and day 35 ranged from 0.9 to16.6 per cent and 1.4 to 62.8 per cent with a mean of 5.90 and 19.64 per cent, respectively. The Bax/Bcl2 ratio ranged from 0.2 to 3.5 with a mean of 0.83. The ratio was predominantly anti-apoptotic, i.e. <1 (77%). A significant association was noted between low AI at day 0 and high total leucocyte count (P=0.02), T-cell phenotype (P=0.043) and high-risk as per NCI category (P=0.025). Significant increase (>30%) in day 35 AI was seen in only six cases.

Interpretation & conclusions:

Our study showed that low AI at day 0 was associated with a high-risk clinical phenotype in paediatric ALL. However, studies on larger group, especially with longer follow up or study of relapse cases, will help draw conclusions regarding apoptosis assessment in paediatric ALL.

The Spectrum of Hypereosinophilia and Associated Clonal Disorders - A Real-World Data Based on Combined Retrospective and Prospective Analysis from a Tropical Setting

OBJECTIVE

To determine the frequency, etiological spectrum and treatment outcome of hypereosinophilia (HE) and hypereosinophilic syndromes (HES) in a tropical setting.

METHODS

A retrospective analysis of hospital data of five years (January 2009 to December 2013) and a comprehensive prospective evaluation of patients presenting with HE/HES over a period of 33 months (January 2014 to September 2016) was performed.

RESULTS

HE/HES was diagnosed in a total of 125 patients during the study period with an estimated prevalence of 0.5-1 case per 100,000 population in our hospital settings. 41 patients were excluded from the final analysis due to lack of sufficient data. Infections, especially helminths were the commonest cause (34%) followed by primary/clonal HE/HES (24%) and reactive HE/HES secondary to various clonal disorders (14.3%). A lymphocytic variant of HES and FIP1L1-PDGFRA positive HES were diagnosed in 3.6% each. Imatinib-responsive BCR-ABL1 negative HE/HES constitute 7.1% in our patients. None of the clinical or routine laboratory features including the age of patients, duration of HE, presence or absence of organomegaly, hemoglobin levels, eosinophil %, absolute eosinophil count, total leukocyte count, platelet counts, serum IgE levels or presence of myelofibrosis could predict or exclude malignancy in patients with HE/HES. The absence of blasts in peripheral blood or the absence of >5% blasts in bone marrow does not exclude primary/clonal HES.

CONCLUSIONS

An underlying malignancy (Primary HE/HES and neoplasms leading to reactive HES; 35.7%) is diagnosed with nearly equal frequency compared to infections (34.5%) in tropical settings. There are no hematological or serological parameters, which can reliably be used to exclude an underlying malignancy, necessitating a thorough follow-up and comprehensive work-up in patients with HE/HES.

Cytogenetic Profile of De Novo B lineage Acute Lymphoblastic Leukemia: Determination of Frequency, Distribution Pattern and Identification of Rare and Novel Chromosomal Aberrations in Indian Patients

BACKGROUND

Chromosomal aberrations identified in acute lymphoblastic leukemia (ALL) have an important role in disease diagnosis, prognosis and management. Information on karyotype and associated clinical parameters are essential to physicians for planning cancer control interventions in different geographical regions.

MATERIALS AND METHODS

In this study, we present the overall frequency and distribution patterns of chromosomal aberrations in both children and adult de novo B lineage ALL Indian patients using conventional cytogenetics, interphase FISH and multiplex RT-PCR.

RESULTS

Among the 215 subjects, cytogenetic results were achieved in 172 (80%) patients; normal karyotype represented 37.2% and abnormal 62.8% with a distribution as follows: 15.3% hypodiploidy; 10.3% hyperdiploidy; 15.8% t(9;22); 9.8% t(1;19); 3.7% t(12;21); 2.8% t(4;11); 2.8% complex karyotypes. Apart from these, we observed several novel, rare and common chromosomal rearrangements. Also, FISH studies using LSI extra-signal dual-color probes revealed additional structural or numerical changes.

CONCLUSIONS

These results demonstrate cytogenetic heterogeneity of ALL and confirm that the incidence of chromosomal abnormalities varies considerably. To the best of our knowledge, this is one of the largest reported series of cytogenetic investigations in Indian B-lineage ALL cases. In addition, ongoing cytogenetic studies are warranted in larger groups of B-lineage ALL cases to identify newly acquired chromosomal abnormalities that may contribute to disease diagnosis and management.

Prevalence of common fusion transcripts in acute lymphoblastic leukemia: A report of 304 cases

AIM

Information about fusion transcripts in acute lymphoblastic leukemia (ALL) is used to risk-stratify patients, decide on the treatment and to detect minimal residual disease. This study was conducted to determine the frequency of common fusion transcripts BCR-ABL, TEL-AML1, MLL-AF4 and E2A-PBX1 for B-ALL and SIL-TAL1 for T-ALL as seen at a tertiary care center in India.

METHODS

Up to 304 new cases of ALL (271 B-ALL and 33 T-ALL) diagnosed on morphology, cytochemistry and immunophenotyping were studied. All were screened for the common fusion transcripts by RT-PCR.

RESULTS

Both our B- (218/271; 80.4%) and T-ALL (26/33; 78.8%) patients were largely children. In the B-ALL children, BCR-ABL was detected in 26/218 (11.9%), E2A-PBX1 in 13/218 (5.9%), TEL-AML1 in 16/218 (7.3%) and MLL-AF4 in 3/218 (1.4%) patients. Adult B-ALL cases had BCR-ABL in 15/53 (28.3%) and E2A-PBX in 2/53 (3.8%); however, no other fusion transcript was detected. SIL-TAL1 was found in four of 26 pediatric (15%) and zero of 7 adult T-ALL cases.

CONCLUSION

The higher incidence of BCR-ABL and lower incidence of TEL-AML1 in our ALL patients, both in children and adults as compared with the West, suggests that patients in India may be biologically different. This difference may explain at least in part the higher relapse rate and poorer outcome in our B-ALL cases.