Molecular Heterogeneity in Acute Promyelocytic Leukemia - a Single Center Experience from India.

Atypical breakpoints and variant APL cases involving alternative chromosomal aberrations are seen in a small subset of acute promyelocytic leukemia (APL) patients. Over seven different partner genes for RARA have been described. Although rare, these variants prove to be a diagnostic challenge and require a combination of advanced cytogenetic and molecular techniques for accurate characterization.

Immunogenetics of chronic lymphocytic leukemia.

Introduction: Cytogenetic aberrations as well as presence of IGVH mutations are the underlying reason for clinical heterogeneity in Chronic Lymphocytic Leukemia (CLL). The presence of IGVH mutations as well as the predominant gene usage shows geographical variations. However, there is no study from India addressing immunogenetics of CLL.

Investigation of recurrent deletion loci specific to conventional renal cell carcinoma by comparative allelotyping in major epithelial carcinomas.

Objective: Loss of heterozygosity (LOH) studies were undertaken to investigate the consistently deleted loci/? tumor suppressor gene loci (TSG) on 3p in conventional renal cell carcinoma (cRCC).

Materials And Methods: LOH studies were performed by polymerase chain reaction (PCR) using 15 micro satellite markers mapped in region 3p12-p26 on 40 paired cRCC tumors and normal kidney at Stages I-IV. Simultaneously, fluorescent in-situ hybridization (FISH) studies were performed to investigate the allelic deletion of fragile histidine triad (FHIT).

Morphological spectrum of leukemic mantle cell lymphoma.

Background: Leukemic involvement in mantle cell lymphoma (MCL) is common, and can be secondary to nodal or extranodal disease or can be de-novo. There is paucity of literature that describes the morphological spectrum.

Aim: This study was aimed at studying the morphological spectrum of leukemic MCL and to correlate the morphology with other features.

Investigation of tumor suppressor genes apart from VHL on 3p by deletion mapping in sporadic clear cell renal cell carcinoma (cRCC).

Objectives: To investigate the most recurrent deletion loci on 3p12-p26 by deletion mapping studies by PCR-LOH and BAC array-FISH in sporadic conventional renal cell carcinoma (cRCC) and further, to evaluate the their clinicopathologic significance in cRCC. Comparative allelotyping studies in cRCC and major epithelial carcinomas (MEC) such as lung, breast, and bladder tumors were also carried out to investigate the specificity of the targeted loci in cRCC.

Subjects And Methods: A total of 40 c-RCC patients were enrolled in this study, categorized in to 2 groups: group I comprises of patients of stages I and II and group II includes patients at stages III and IV.

RUNX1 aberrations in ETV6/RUNX1-positive and ETV6/RUNX1-negative patients: its hemato-pathological and prognostic significance in a large cohort (619 cases) of ALL.

A large-cohort study (619) of acute lymphoblastic leukemia (ALL) revealed an ETV6/RUNX1 (previously known as TEL/AML1) incidence of 18% in pediatric B-cell precussor ALL, indicating no geographical heterogeinity. Association of CD34-negative phenotype, peak incidence in the 3- to 7-year age group, and a comparatively low frequency of ETV6 homologue loss in ETV6/RUNX1-positive cases were distinct findings in this series. Additional genetic changes, such as ETV6 loss, extra RUNX1, ETV6/RUNX1 duplication, and MLL aberrations in the ETV6/RUNX1-positive group, supported the hypothesis of the ETV6/RUNX1 leukemogenic model that these secondary changes are necessary for leukemogenesis rather than progression of disease.

Coexistence of ETV6/RUNX1 and MLL aberrations in B-cell precursor acute lymphoblastic leukemia discloses a small subclass of BCP-ALL.

Out of 76 pediatric cases of B-cell precursor acute lymphoblastic leukemia (BCP-ALL) positive for ETV6/RUNX1 (previously TEL/AML1) resulting from t(12;21), 7 cases revealed coexistence of ETV6/RUNX1 and MLL aberrations. One case of der(21) duplication with ETV6/RUNX1 exhibited a novel MLL translocation variant t(6;11)(p21.1p23;q13q25), with translocation of 3' telomeric MLL and deletion of 5' centromeric MLL.

p53 gene gets altered by various mechanisms: studies in childhood sarcomas and retinoblastoma.

Background: Somatic and constitutional mutation screening of p53 in childhood sarcomas and retinoblastoma was investigated by a multitechnical approach to evaluate its role in the development/progression by somatic mutation events and/or genetic predisposition.

Material/methods: The studies were carried out on a cohort of 100 sarcoma cases, i.e.

Identification of various MLL gene aberrations that lead to MLL gene mutation in patients with acute lymphoblastic leukemia (ALL) and infants with acute leukemia.

Studies were done to investigate MLL gene aberrations using Conventional Cytogenetics, Southern blotting as well as FISH using a panel of probes on 218 cases which included 206 cases of pediatric/young adult ALL and 12 cases of infantile acute leukemias from Tata Memorial Hospital, India. The incidence of MLL gene rearrangements in acute lymphoblastic leukemia (ALL) was 9.4% which included infants as well as pediatric/young adults.

Chromosomal rearrangement in Down syndrome with acute myeloid leukemia.

The incidence of acute leukemia in children with Down syndrome (DS) is high as compared to general population. Recent findings have demonstrated that DS children with acute myeloid leukemia (AML) have the highest event free survival rates with high dose cytosine arabinoside (Ara-C). We present 3 year-old DS female child with AML-M5, whose chromosomal analysis revealed constitutional t(21;21) alongwith del(5)(q31q33) and a unique translocation t(16;20)(q13;q12).