Biswajit Dubashi

Pharmacogenetics of methotrexate in acute lymphoblastic leukaemia: why still at the bench level?

PurposeThe antifolate drug methotrexate (MTX) was introduced into clinical practice about 60 years ago and remains an important component of different acute lymphoblastic leukemia (ALL) treatment protocols. It acts by inhibiting several enzymes in the folate pathway, thereby resulting in the disruption of folate homeostasis. To date, treatment regimens have not been personalized despite there being experimental evidence that gene polymorphisms of folate metabolizing enzymes affect MTX response. The aim of this review was to evaluate the influence of genetic polymorphisms of the enzymes involved in the MTX pathway on ALL treatment outcomes and identify factors underlining the failure to personalize MTX therapy.MethodsWe conducted a literature search in PUBMED and Goggle scholar using the following key words: methotrexate, polymorphism, acute lymphoblastic leukemia, pharmacogenetics, pharmacogenomics and personalized mediciner.ResultsThe reasons for the failure to personalize MTX therapy may be due to (1) most studies involving single-center, small-sized cohorts, (2) differences in MTX dose across different protocols, (3) failure to consider minimal residual disease as a risk factor for post-induction treatment, (4) differences in outcome criteria between studies and (5) failure to consider the folate levels of a patient before initiation of MTX therapy. Although high-throughput techniques allow the mapping of thousands of genetic polymorphisms in a single run, it remains a major challenge to dissect out folate-metabolizing enzymes which have a high impact on the efficacy and toxicity of MTX and which, therefore, could be the targets for intervention.ConclusionsProspective pharmacogenetic studies which consider all of the above-mentioned factors should be undertaken to facilitate the design of personalized MTX treatment for ALL patients.

Docetaxel-induced hand foot syndrome: "No dose is a safe dose"

Docetaxel is an important chemotherapeutic agent used in the management of many solid tumors. The most important side effect of this drug is myelosupression. We report a case of carcinoma breast that developed severe hand-foot syndrome at 75 mg/m2 doses of docetaxel. The exact mechanism of this side effect in not known. All the physicians using this drug must be aware of this side effect.

Genotype Distribution of Dihydrofolatereductase Variants and their Role inDisease Susceptibility to Acute Lymphoblastic Leukemia in Indian Population: An Experimental and Computational Analysis

Objectives: To establish the allele and genotype frequencies of dihydrofolate reductase (DHFR) -317A>G and -680C>A variants in Indian population, to find the association of these variants with the risk of acute lymphoblastic leukemia (ALL) and to analyze the effects of non-synonymous SNPs (nsSNPs) and 3’untranslated region (3’UTR)variants of DHFR gene on its structure and function using in-silico tools. Methods: A total of 235 unrelated healthy volunteers (controls) and 127 ALL patients (cases) were recruited for the study. DNA was extracted from peripheral leucocytes. Genotyping of DHFR polymorphisms was done by realtime PCR. We investigated the deleterious effect of nsSNPs and variants in 3’UTR of DHFR gene through computational platforms. Results: In the present study, the frequency of DHFR -317G and -680 A alleles was found to be 33.3% and 59.8% respectively. The studied DHFR variants (rs408626 and rs442767) did not confer a significant risk for ALL. Insilico analysis revealed that three nsSNPs potentially affect the structure, function and activity of the DHFR protein. Four microRNA binding sites were found to be highly affected due to 3’UTR SNPs. Further, docking simulation suggested that the order of binding affinity of methotrexate towards native and all three mutant forms of DHFR is D153V (rs121913223)>native>G18R (rs61736208)>D187Y (rs200904105). Conclusion: This is the first study to report the normative genotype distribution of DHFR variants in Indian population and also to report that DHFR (-317A>G and -680C>A) variants do not confer a potential risk for development of ALL. Inter-ethnic differences exist in the distribution of DHFR variant genotypes, and this can lead to variability in therapeutic response to DHFR substrates. Protein sequence analysis revealed rs200904105 influences the phosphorylation process (post-translational modification) of DHFR and docking simulation suggested methotrexate to have a higher affinity towards rs121913223 mutant form. Therefore, studies are warranted to explore the clinical impact of these variants in the Indian population.

A Rare Case of Adult Acute Lymphoblastic Leukemia Presenting with Paraparesis and Multiple Osteolytic Lesions

Acute lymphoblastic leukemia presenting with bone involvement and multiple osteolytic lesions has been commonly reported in pediatric population. Various myeloid and lymphoid malignancies can rarely present with bony lesions. We are reporting an adult female patient with acute lymphoblastic leukemia who presented with paraparesis and multiple osteolytic lesions in skull initially giving false impression of multiple myeloma.

Prescription errors in cancer chemotherapy: Omissions supersede potentially harmful errors

Objective: To estimate the frequency and type of prescription errors in patients receiving cancer chemotherapy. Settings and Design: We conducted a cross-sectional study at the day care unit of the Regional Cancer Centre (RCC) of a tertiary care hospital in South India. Materials and Methods: All prescriptions written during July to September 2013 for patients attending the out-patient department of the RCC to be treated at the day care center were included in this study. The prescriptions were analyzed for omission of standard information, usage of brand names, abbreviations and legibility. The errors were further classified into potentially harmful ones and not harmful based on the likelihood of resulting in harm to the patient. Descriptive analysis was performed to estimate the frequency of prescription errors and expressed as total number of errors and percentage. Results: A total of 4253 prescribing errors were found in 1500 prescriptions (283.5%), of which 47.1% were due to omissions like name, age and diagnosis and 22.5% were due to usage of brand names. Abbreviations of pre-medications and anticancer drugs accounted for 29.2% of the errors. Potentially harmful errors that were likely to result in serious consequences to the patient were estimated to be 11.7%. Conclusions: Most of the errors intercepted in our study are due to a high patient load and inattention of the prescribers to omissions in prescription. Redesigning prescription forms and sensitizing prescribers to the importance of writing prescriptions without errors may help in reducing errors to a large extent.

Frequency distribution of DNA repair genes ERCC1 and ERCC2 polymorphisms in South Indian healthy population.

DNA repair genes are crucial in maintaining the integrity of the whole genome. Single nucleotide polymorphisms (SNPs) in DNA repair genes have been attributed to the development of various cancers. SNPs of DNA repair genes (ERCC1 and ERCC2) have been implicated in the causation of various cancers as well as inter-individual variability in the therapeutic outcomes of platinum based therapy. Thus establishing the frequency of these functional SNPs in the healthy population is of significance. The present study was aimed to establish the allele and genotype frequencies of ERCC1 (19007C>T, rs11615; 8092C>A, rs3212986) and ERCC2 (Asp312Asn, rs1799793) genes in South Indian healthy population and to compare the data from HapMap populations. The study population consisted of 128 healthy South Indian unrelated individuals of either sex aged between 18 and 60 years. Standard phenol-chloroform method was used to extract DNA from peripheral leukocytes. The genotype of DNA repair gene polymorphisms was determined by quantitative real-time polymerase chain reaction using TaqMan genotyping assay. The observed frequency of the studied polymorphisms followed Hardy-Weinberg equilibrium (p>0.05). The frequencies of the minor alleles of the SNPs rs11615 (T), rs3212986 (A) and rs1799793 (A) were 43.8%, 29.3% and 35.6%, respectively. Gender-based analysis showed no significant difference in the frequency pattern. The observed allele and genotype frequencies showed significant ethnic difference between South Indians and other HapMap populations. This is the first study to provide the normative frequency data of allele and genotype distribution of three SNPs of ERCC1 and ERCC2 in South Indian healthy population. It might be useful in future genotype-phenotype association studies, especially for predicting the efficacy and adverse events of platinum based drugs.

Adverse drug reactions of imatinib in patients with chronic myeloid leukemia: A single-center surveillance study.

Objective: To monitor the adverse drug reactions (ADRs) associated with imatinib treatment in patients with chronic myeloid leukemia (CML) in a tertiary care hospital. Materials and Methods: The study was carried out by the Departments of Pharmacology and Medical Oncology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India. The study was carried out from March 2012 to February 2014. The ADRs were reported in a suspected Adverse Drug Reaction Reporting form, provided by the Central Drugs Standard Control Organization (CDSCO), Ministry of Health and Family Welfare, Government of India. The ADRs were analyzed for their pattern, causality and severity. Results: A total of 326 ADRs from 81 patients were reported during the study period. The hematological toxicities were much more prominent than the non-hematological toxicities in this study. The prevalence of thrombocytopenia (21.17%) was higher compared with other reactions. Further analysis showed that most of the ADRs were mild to moderate in nature. The causality assessment revealed that the majority of the ADRs belonged to the possible category. Conclusion: The present study in a tertiary care hospital suggests that hematological toxicities are predominant in CML patients treated with imatinib mesylate. The blood and lymphatic system (38.96%) was the most affected, with imatinib therapy and thrombocytopenia (21.17%) being the most commonly encountered ADRs in the present study. Thorough monitoring of ADRs is warranted for better treatment outcomes.

Anticancer drug induced palmar plantar erythrodysesthesia.

BACKGROUND Palmar plantar erythrodysesthesia (PPE) is a dose limiting toxicity of anticancer agents. In some cases it may mandate for discontinuation of anticancer agents. Evaluation of data of PPE among reported adverse drug reactions (ADRs) from the Department of Medical Oncology could quantify the burden. AIM To evaluate and analyse the PPE among reported ADRs from medical Oncology. MATERIALS AND METHODS The data of all cases of reported PPE were collected during January 2012 to September 2013 and were analysed with WHO causality assessment scale. The severity was clinically graded. The follow-up data regarding outcome of ADRs were also noted. RESULTS During the study period of 21 months a total of 1418 ADRs have been reported from 1076 patients. Among them PPE was reported from 31 cases (2.9%). Majority (32.2%) of these patients were on chemotherapy for breast cancer. Patients age ranged from 17 to 68 y and the median age was 50 y. There were 18 female (58%) and 13 male patients (42%). Capecitabine was the leading drug involved in PPE, reported with 20 cases (64.5%), and followed by docetaxel with 5 cases (16.1%). Majority (67.7%) of the reactions was categorized as certain and 64.5% was grade II severity clinically. CONCLUSION Our findings show that PPE accounts for 2.9% of total reported ADRs from Medical Oncology during 21 months. Majority of the reactions were classified as certain. Capecitabine is commonly implicated drug.

Allele and Genotype Distributions of DNA Repair Gene Polymorphisms in South Indian Healthy Population

Various DNA repair pathways protect the structural and chemical integrity of the human genome from environmental and endogenous threats. Polymorphisms of genes encoding the proteins involved in DNA repair have been found to be associated with cancer risk and chemotherapeutic response. In this study, we aim to establish the normative frequencies of DNA repair genes in South Indian healthy population and compare with HapMap populations. Genotyping was done on 128 healthy volunteers from South India, and the allele and genotype distributions were established. The minor allele frequency of Xeroderma pigmentosum group A (XPA) G23A, Excision repair cross-complementing 2 (ERCC2)/Xeroderma pigmentosum group D (XPD) Lys751Gln, Xeroderma pigmentosum group G (XPG) His46His, XPG Asp1104His, and X-ray repair cross-complementing group 1 (XRCC1) Arg399Gln polymorphisms were 49.2%, 36.3%, 48.0%, 23.0%, and 34.0% respectively. Ethnic variations were observed in the frequency distribution of these polymorphisms between the South Indians and other HapMap populations. The present work forms the groundwork for cancer association studies and biomarker identification for treatment response and prognosis.

Low grade follicular lymphoma with high proliferation index; diagnostic and management issues

Follicular Lymphoma (FL) is the second most common B-Non Hodgkin Lymphoma after diffuse large B cell lymphoma (DLBCL). Low grade FL is known for its indolent behavior; however, one subset of FL behave aggressively and may require intensive therapy. One of the diagnostic issues in FL is to identify this subgroup of cases. Proliferation index can have prognostic importance in this subset of cases. We discuss one case of low grade FL with a paradoxically high proliferative index. A 63 year male presented with generalized lymphadenopathy of one year duration, which was gradually increasing in size. On examination, patient had bilateral cervical, axillary and inguinal nodes. Biopsy of the left cervical lymph node was reported as FL-Grade 2, with high proliferative Index (60%). The patient was put on CHOP regimen targeted for high grade lymphomas, and had complete remission. High proliferative index in FL is a poor prognostic factor irrespective of the histologic grade. So, proliferative index should be assessed in all cases of FL as an adjunct to histologic grading.