Clinical value of fluorescence in situ hybridization with MDM2 and DDIT3 probe in diagnosis of liposarcoma / 北京大学学报(医学版)

OBJECTIVE@#To investigate the value of using MDM2 amplification probe and DDIT3 dual-color, break-apart rearrangement probe fluorescence in situ hybridization (FISH) technique in the diagnosis of liposarcoma.@*METHODS@#In the study, 62 cases of liposarcoma diagnosed in Peking University First Hospital from January 2015 to December 2019 were analysed for clinicopathological information. Of these 62 cases of liposarcoma, all were analysed for MDM2 amplification and 48 cases were analysed for DDIT3 rearrangement using a FISH technique. Our study aimed to evaluate the status of MDM2 and DDIT3 by FISH in liposarcoma and correlate it with diagnosis of different subtypes of liposarcoma. The subtypes of liposarcoma were classified according to the FISH results, combined with the relevant clinicopathological features.@*RESULTS@#The patients aged 31-89 years (mean: 59 years) with a 1.75:1 male to female ratio. Histologically, there were 20 cases of atypical lipomatous tumour/well-differentiated liposarcoma (ALT/WDLPS), 26 cases of dedifferentiated liposarcoma (DDLPS), 13 myxoid liposarcoma (MLPS) and 3 pleomorphic liposarcoma (PLPS). Tumors with DDLPS (23/26) and WDLPS (8/20) were localized retroperitoneally, while both tumours of MLPS and PLPS were localized extra-retroperitoneally, and the difference of sites among the four subtypes of liposarcoma was statistically significant (P < 0.05). Histologically, varied mucoid matrix could be observed in the four subtypes of liposarcoma, and the difference was statistically significant (P < 0.05). MDM2 gene amplification was demonstrated in all cases of ALT/WDLPS and DDLPS (100%, 20/20 and 26/26 respectively); DDIT3 gene rearrangement was noted only in MLPS (100%, 13/13); most cases of DDLPS (96.2%, 25/26) and ALT/WDLPS (83.3%, 5/6, 6 cases selected for detection) demonstrated the picture of amplification of the DDIT3 telomeric tag. According to the instructions of DDIT3 break-apart rearrangement probe, the 5' telomere probe and 3' centromere probe spanned but did not cover the DDIT3 gene itself, on the contrary, the 5' telomere probe covered the CDK4 gene, while the DDIT3 and CDK4 gene were located adjacent to each other on chromosome, therefore, when the amplification signal appeared on the telomeric tag of the DDIT3 rearrangement probe, it indeed indicated the CDK4 gene amplification rather than the DDIT3 gene rearrangement. Then the 10 cases with DDIT3 telomeric tag amplification were selected for CDK4 and DDIT3 gene amplification probe FISH tests, and all the cases showed CDK4 gene amplification (100%, 10/10) and two of the 10 cases demonstrated co-amplification of CDK4 and DDIT3 (20%, 2/10); DDIT3 polysomy detected by DDIT3 gene rearrangement probe was found in 1 case of DDLPS and 2 cases of PLPS (66.7%, 2/3) with morphology of high-grade malignant tumour and poor prognosis.@*CONCLUSION@#Our results indicate that a diagnosis of different subtype liposarcoma could be confirmed based on the application of MDM2 and DDIT3 FISH, combined with clinicopathological findings. It is also noteworthy that atypical signals should be correctly interpreted to guide correct treatment of liposarcomas.

Genetic analysis of a case of B-acute lymphoblastic leukaemia with double Philadelphia chromosomes and double derivative chromosome 9s / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a rare case of acute B-lymphocytic leukemia (B-ALL) with double Philadelphia chromosomes (Ph) and double derivative chromosome 9s [der(9)].@*METHODS@#A patient with double Ph and double der(9) B-ALL who presented at Shanghai Zhaxin Intergrated Traditional Chinese and Western Medicine Hospital in June 2020 was selected as the subject. Bone marrow morphology, flow cytometry, G-banding karyotyping, fluorescence in situ hybridization (FISH), genetic testing and chromosomal microarray analysis (CMA) were used to analyze bone marrow samples from the patient at various stages.@*RESULTS@#At initial diagnosis, the patient's bone marrow morphology and flow immunotyping have both supported the diagnosis of B-ALL. G-banded karyotyping of the patient indicated double Ph, in addition with hyperdiploid chromosomes involving translocations between chromosomes 9 and 22. BCR-ABL1 fusion gene was positive. Genetic testing at the time of recurrence revealed presence of a heterozyous c.944C>T variant in the kinase region of the ABL1 gene. FISH showed a signal for ABL1-BCR fusion on both chromosome 9s. CMA showed that the mosaicism homozygosity ratio of chromosome 9 was about 40%, and the mosaicism duplication ratio of chromosome 22 was about 43%.@*CONCLUSION@#Since both der(9) homologs were seen in 40% of cells, the possible mechanism for the double der(9) in this patient may be similar to that of double Ph, which might have resulted from non-disjunction during mitosis in the Ph chromosome-positive cell clone.

Comparison of detection rates of chromosome G-banding karyotype analysis and fluorescence in situ hybridization among children with sex chromosome mosaicisms / 中华医学遗传学杂志

OBJECTIVE@#To explore the coincidence rate of G-banding karyotype analysis and fluorescence in situ hybridization (FISH) for the diagnosis of children with sex chromosome mosaicisms.@*METHODS@#A retrospective analysis was carried out for 157 children with suspected sex chromosome abnormalities who had presented at Shenzhen Children's Hospital from April 2021 to May 2022. Interphase sex chromosome FISH and G-banding karyotyping results were collected. The coincidence rate of the two methods in children with sex chromosome mosaicisms was compared.@*RESULTS@#The detection rates of G-banding karyotype analysis and FISH were 26.1% (41/157) and 22.9% (36/157) , respectively (P > 0.05). The results of G-banding karyotype analysis showed that 141 cases (89.8%) were in the sex chromosome homogeneity group, of which only 5 cases (3.5%) were inconsistent with the results of FISH. There were 16 cases (10.2%) in the sex chromosome mosaicism group, of which 11 cases (68.8%) were inconsistent with the results of FISH. There was a statistical difference between the two groups in the coincidence rate of the results of the two methods (P < 0.05).@*CONCLUSION@#No significant difference was found between G-banding karyotype analysis and FISH in the detection rate of chromosome abnormalities. The coincidence rate in the mosaicism group was lower than that in the homogeneity group, and the difference was statistically significant. The two methods should be combined for clinical diagnosis.

Application of Flow Cytometry Combined Fluorescence in Situ Hybridization to Indentify the Lymphocyte Subtypies with Epstein-Barr Virus Infection / 中国实验血液学杂志

OBJECTIVE@#To establish the technique that take the advantages of flow cytometry combined fluorescence in situ hybridization (Flow-FISH) to identify the Epstein-Barr virus(EBV) infected lymphocyte subtypies in patients' peripheral blood sample.@*METHODS@#Peripheral Blood monocyte from 9 patients with EBV infection enrolled at Children's Hospital in Chongqing Medical University were isolated by Ficoll-paque centrifugal separation. The expressions of EBER1, EBER2 in cell were detected by qRT-PCR. The surface markers of cell were detected by Flow cytometry after staining with their antibodies. The cell was treated Fix-Permeabilization Buffer before hybridization with fluorescent labeled probe at 37 ℃ overnight. The cell status, surface markers and targeted mRNA are detected by flow cytometry and fluorescence microscope.@*RESULTS@#It was optimized that the Fix-Permeabilization Buffer and recipe with 0.2% Tween-20 were picked out as providing a good cell integrity and high resolution of surface markers. Hybridization with 20% formamide and 7% dextran sulfate at 37 ℃ overnight is the optimal hybridization condition as a good hybridization effect, a detectable cell integrity and a high resolution of cell markers under flow cytometry detection. Finally, upon the established Flow-FISH method, lymphocyte subpopulations of the EBV+ cells from cell lines and blood samples of patients were identified successfully.@*CONCLUSION@#A Flow-FISH technology is established, which can be applied in the identification of EBV infected cell subtypes. This research provides a foundmental for its application in clinical test in EBV+ related proliferative diseases.

Citogenética de las hemopatías malignas en la era de la secuenciación / Cytogenetics of malignant hemopathies in the sequencing era

Las neoplasias hematológicas se caracterizan por un gran número y complejidad de alteraciones genéticas, desde la formación de genes de fusión a partir de translocaciones e inversiones cromosómicas hasta mutaciones génicas y alteraciones epigenéticas que han permitido la identificación de nuevos oncogenes y genes supresores de tumores responsables de su etiología. Al abordar el estudio genético de las leucemias se utilizan múltiples técnicas como la citogenética convencional, citogenética molecular (hibridaciónin situ por fluorescencia (FISH), esta última con una mayor sensibilidad, especificidad y rapidez que permiten el diagnóstico, la estratificación pronóstica y seguimiento de la enfermedad. Las técnicas anteriores se integran con técnicas de biología molecular, secuenciación génica, entre otras, que permiten el hallazgo de nuevos marcadores genéticos con una mejor caracterización de las hemopatías malignas y la posibilidad del desarrollo de nuevos fármacos específicos que actúen sobre la diana molecular. El objetivo fue revisar la utilidad de la citogenética y la secuenciación génica en el estudio de la leucemia mieloide aguda y la leucemia linfocítica crónica. Ante las ventajas, desventajas y limitaciones de estas técnicas genéticas es necesario utilizarlas de forma complementaria y nunca excluyente(AU)

Hematological neoplasms are characterized by a large number and great complexity of genetic disorders, from the formation of fusion genes after chromosomal translocations and inversions to gene mutation and epigenetic disorders that have permitted the identification of new oncogenes and tumor-suppressing genes responsible for their etiology. When addressing the genetic study of leukemias, multiple techniques are used, such as conventional cytogenetics, molecular cytogenetics, and fluorescence in situ hybridization (FISH), the latter having the higher degree of sensitivity, specificity and speed, which allow diagnosis, prognostic stratification and follow-up of the disease. The previous techniques are integrated with molecular biology techniques, gene sequencing, among others, which allow discovery of new genetic markers with better characterization of malignant hemopathies and the possibility of developing new specific drugs against the molecular target. The objective was to review the usefulness of cytogenetics and gene sequencing in the study of acute myeloid leukemia and chronic lymphocytic leukemia. Given the advantages, disadvantages and limitations of these genetic techniques, it is necessary to use them in as complementary but never exclusive management ways(AU)

Características del diagnóstico prenatal por hibridación fluorescente in situ en Cuba / Features of the prenatal diagnosis by fluorescence in situ hybridization in Cuba

Introducción: El diagnóstico prenatal mediante la hibridación fluorescente in situ disminuye el tiempo de diagnóstico al no ser necesario el cultivo celular. Objetivo: Describir las características y experiencias del diagnóstico prenatal por hibridación fluorescente in situ en Cuba. Método: En amniocitos in situ se aplicaron sondas CEP y LSI para la detección de aneuploidías de los cromosomas 21,18,13, X y Y y sondas LSI para la detección de deleciones asociadas a síndromes de microdeleción. Resultados: Se remitieron al Centro Nacional de Genética Médica 629 casos de alto riesgo genético. Prevaleció la indicación de alteraciones fetales detectadas por ecografía. En 612 (97 por ciento) casos se obtuvo un diagnóstico satisfactorio, entre ellos, 50 (8,1 por ciento) casos positivos, con predominio del síndrome Down en 26 casos. Se corroboraron por citogenética convencional 312 casos con 98 por ciento de concordancia con los resultados obtenidos por hibridación fluorescente in situ. Se utilizó el líquido amniótico refrigerado para corroborar casos de diagnóstico dudoso obtenido por citogenética y se detectaron 3 fetos con mosaicos cromosómicos, el origen de un cromosoma marcador y la definición del sexo fetal en un caso. Conclusiones: Con la tecnología por hibridación fluorescente in situ el diagnóstico prenatal logra una segura opción de análisis en aquellos casos de embarazos de alto riesgo genético. Debido a limitaciones tecnológicas, la prueba por hibridación fluorescente in situ en células amnióticas en interfase, se ha adaptado a nuestras condiciones, para lograr siempre un diagnóstico seguro con el menor perjuicio posible a la embarazada, el feto y su familia(AU)

Introduction: Prenatal diagnosis by fluorescent in situ hybridization decreases the time of diagnosis not being necessary the cell culture. Objective: To describe the characteristics and experiences of prenatal diagnosis by fluorescent in situ hybridization in Cuba. Method: In in situ amniocytes CEP catheters were applied and LSI for the detection of aneuploidies of the 21,18,13, X and Y chromosomes, and LSI catheters for the detection of deletions associated with microdeletion syndromes. Results: 629 cases of high genetic risk were referred to the National Center of Medical Genetics. There was a prevalence of the indication of fetal abnormalities detected by ultrasound. In 612 (97 percent) cases the diagnosis was achieved in a satisfactory form, among them 50 (8.1 percent) positive cases, with predominance of Down syndrome in 26 cases. There were corroborated 312 cases by conventional cytogenetics with 98 percent of agreement with the results obtained by fluorescent in situ hybridization. It was used the cooled amniotic fluid to corroborate cases of uncertain diagnosis obtained by cytogenetics and there were detected 3 fetuses with chromosomal mosaics, the origin of a marker chromosome and the definition of fetal sex in one case. Conclusions: With the technology by fluorescent in situ hybridization, the prenatal diagnosis achieved a safe analysis option in cases of genetic high-risk pregnancies. Due to technological limitations, the test by fluorescent in situ hybridization in amniotic cells in interphase has adapted to the conditions in order to always achieve a safe diagnosis with the less possible damage to the pregnant women, the fetus and its family(AU)

Caso atípico de leucemia mieloide aguda con coexistencia de NPM1-A e inversión del cromosoma 16 / A rare case of acute myeloid leukemia with coexistence of NPM1-A mutation and chromosome 16 inversion

Introducción: La leucemia mieloide aguda (LMA) es un grupo heterogéneo de desórdenes clonales con una gran variabilidad en términos de patogénesis, características morfológicas, genéticas e inmunofenotípicas. Las mutaciones en el gen NPM1 representan una de las más comunes en las LMA y está asociada con una respuesta clínica favorable. Por citogenética, la inversión del cromosoma 16 define el subgrupo de las LMA de factor de unión al grupo con un pronóstico favorable. Objetivo: Describir un caso con diagnóstico de LMA en los cuales el estudio molecular del gen NPM1 y de la inv(16) fueron positivos. Caso clínico: A nivel molecular, la hibridación in situ fluorescente fue positivo a la inv(16) y por biología molecular fue positivo tanto a la inv(16) como al gen NPM1-A, elementos de baja frecuencia de aparición. Se le administró a la paciente un esquema de poliquimioterapia no intensiva para mejorarla clínicamente. Después de una mejoría clínica inicial, la paciente comenzó con complicaciones y falleció. Conclusiones: La coexistencia de estas dos mutaciones es muy poco frecuente en pacientes con LMA, y a pesar de ser de buen pronóstico la paciente falleció a los pocos días de tratamiento(AU)

Introduction: Acute myeloid leukemia (AML) is a heterogeneous group of clonal disorders with great variability in terms of pathogenesis, morphological, genetic and immunophenotypic characteristics. NPM1 mutations represent one of the most common in AML and are associated with favorable clinical response. By cytogenetics, chromosome 16 inversion defines, with a favorable prognosis, the core‐binding factor for the subgroup of AMLs Objective: To describe a AML case in which the molecular study of the NPM1 gene and the chromosome 16 inversion were positive. Clinical case: At the molecular level, fluorescent in situ hybridization was positive for chromosome 16 inversion and, by molecular biology, it was positive for both chromosome 16 inversion and for the NPM1-A gene, elements with a low frequency of appearance. The patient was administered a non-intensive combination as part of a chemotherapy regimen to improve her clinical status. After initial clinical improvement, the patient began with complications and died. Conclusions: The coexistence of these two mutations is very rare in patients with AML. Despite presenting a good prognosis, the patient died after a few days of treatment(AU)

Características citogenéticas y detección de anormalidades de alto riesgo en mieloma múltiple / High risk cytogenetic abnormalities in patients with multiple myeloma

Background: Cytogenetic abnormalities observed in the bone marrow of patients with multiple myeloma (MM) are an important prognostic factor for risk stratification. Aim: To investigate karyotype characteristics and frequency of the high-risk cytogenetic abnormalities t(4;14), t(14;16) and del(17p) in Chilean patients with MM. Material and Methods: We studied 30 patients with MM by conventional cytogenetics (CC) and fluorescent in situ hybridization of plasma cells selected using cytoplasmic immunoglobulin staining (cIg-FISH). Results: Overall, the two techniques in combination allowed us to identify clonal genetic abnormalities in 47% of patients. The t(4;14) abnormality was observed in 19% of patients, del(17p) was observed in 10% of patients, and t(14;16) was not detected. Conclusions: Our results showed frequencies of high-risk abnormalities similar to those reported abroad. Cytogenetic studies should be performed routinely for all MM patients at the moment of diagnosis.

Disponibilidad de técnicas moleculares para niños con tumores de difícil caracterización. Un problema en la Oncopatología pediátrica. Aplicación y difusión de técnicas de diagnóstico complementarias en el ámbito público / Availability of molecular techniques for children with difficult-to-characterize tumors. A problem in pediatric oncopathology. Application and diffusion of complementary diagnostic techniques in the public setting

La revolución de la biología molecular y el desarrollo de la investigación biomédica básica para el diagnóstico y posterior manejo del cáncer infantil han llevado a la necesidad de organización de grupos interdisciplinarios de profesionales, los cuales se encargan de afrontar los nuevos desafíos diagnósticos y terapéuticos. Los sarcomas indiferenciados pediátricos constituyen un grupo heterogéneo de neoplasias malignas de aspecto primitivo y polifenotípico. La categorización de gran parte de este tipo de tumores es posible gracias a la aplicación de técnicas moleculares complementarias al estudio histopatológico. El objetivo del presente estudio fue recategorizar sarcomas indiferenciados mediante la implementación de una nueva metodología diagnóstica. Se efectuaron técnicas de inmunohistoquimica (IHQ), FISH de interfase y RT-PCR a partir de tejido fijado en formol e incluido en parafina en 144 casos de sarcomas indiferenciados. Se logró la recategorización del 95.1% de los casos, arribando a 24 diagnósticos diferentes. Sólo un 4.9% permanece aún como sarcoma indiferenciado o inclasificable. Los resultados alcanzados por este estudio demuestran la importancia de contar con nuevas herramientas diagnósticas a nivel molecular y recursos humanos especializados que posibiliten su correcta implementación para el diagnóstico de neoplasias de difícil caracterización (AU)

The revolution of molecular biology and the development of basic medical research for the diagnosis and subsequent management of childhood cancer have led to a need to organize interdisciplinary groups of professionals in charge of facing new diagnostic and treatment challenges. Childhood undifferentiated sarcomas are a heterogeneous group of malignant neoplasms that are primitive in appearance and have polyphenotypic features. Categorization of a large part of this type of tumor has become possible with molecular techniques as a complement to histopathological studies. The aim of this study was to categorize undifferentiated sarcomas using new diagnostic tools. Immunohistochemistry (IHC), interfase FISH, and RT-PCR techniques were used on formalin-fixed and paraffin-embedded tissues of 144 cases of undifferentiated sarcomas. Overall, 95.1% of the cases could be recategorized resulting in 24 different diagnoses. In only 4.9% the diagnosis of undifferentiated or unclassifiable sarcoma was maintained. These results emphasize the importance of the availability of new diagnostic tools at the molecular level and specialized human resources enabling adequate implementation for the diagnosis of difficult-to-characterize neoplasms (AU)

Protocol for chromosome-specific probe construction using PRINS, micromanipulation and DOP-PCR techniques

ABSTRACT Chromosome-specific probes have been widely used in molecular cytogenetics, being obtained with different methods. In this study, a reproducible protocol for construction of chromosome-specific probes is proposed which associates in situ amplification (PRINS), micromanipulation and degenerate oligonucleotide-primed PCR (DOP-PCR). Human lymphocyte cultures were used to obtain metaphases from male and female individuals. The chromosomes were amplified via PRINS, and subcentromeric fragments of the X chromosome were microdissected using microneedles coupled to a phase contrast microscope. The fragments were amplified by DOP-PCR and labeled with tetramethyl-rhodamine-5-dUTP. The probes were used in fluorescent in situ hybridization (FISH) procedure to highlight these specific regions in the metaphases. The results show one fluorescent red spot in male and two in female X chromosomes and interphase nuclei.

Una revisión actualizada del síndrome de deleción (monosomía) 1p36 / An updated review of 1p36 deletion (monosomy) syndrome

El síndrome de monosomía 1p36 forma parte del grupo de enfermedades conocidas como «enfermedades de baja prevalencia¼ o «enfermedades raras¼. El objetivo del presente trabajo es revisar los hallazgos de los principales estudios realizados en niños diagnosticados con el síndrome de monosomía 1p36. El fenotipo del síndrome de deleción (monosomía) 1p36 delineado desde 1997 incluye rasgos craneofaciales dismórficos: fontanela anterior grande, cejas rectas, ojos hundidos, epicanto, raíz/puente nasal anchos, hipoplasia del tercio medio facial, orejas implantadas anormalmente, filtrum largo y barbilla puntiaguda; alteraciones neurológicas: convulsiones e hidrocefalia (en casos aislados); malformaciones cerebrales observadas en imágenes por resonancia magnética (IRM): ensanchamiento ventricular, ensanchamiento de espacios subaracnoideos, alteraciones morfológicas del cuerpo calloso, entre otras. La IRM evidencia en algunos pacientes atrofia cortical, retraso en la mielinización, áreas multifocales hiperintensas, leucomalacia periventricular y heterotopia periventricular. Estos pacientes cursan con discapacidad intelectual, retrasos en el desarrollo motor, de la comunicación, del lenguaje, en el área personal-social y en la conducta adaptativa. También se observan alteraciones en el sistema auditivo, visual, cardiaco, endocrino, genitourinario, dermatológico y esquelético. Conclusiones: Existen datos de aproximadamente 100 casos en el mundo desde 1981. Esta enfermedad rara es el síndrome más común de microdeleción subtelomérica. La técnica de hibridación in situ con fluorescencia y la técnica de hibridación genómica comparativa (array-CGH) son las que mejor permiten su diagnóstico. Por el momento no existe ningún tratamiento médico efectivo para esta enfermedad.

The Monosomy 1p36 deletion syndrome is part of the group of diseases known as Rare Diseases. The objective of the present work is to review the characteristics of Monosomy 1p36 deletion syndrome. The monosomy 1p36 deletion syndrome phenotype includes: dysmorphic craniofacial features; large anterior fontanelle, unibrow, deep-set eyes, epicanthus, wide nasal root/bridge, mandible hypoplasia, abnormal location of the pinna, philtrum and pointed chin; neurological alterations: seizures and hydrocephalus (in some cases). Cerebral malformations: ventricular hypertrophy, increased subarachnoid space, morphological alterations of corpus callosum, cortical atrophy, delays in myelinisation, periventricular leukomalacia and periventricular heterotopia. These alterations produce intellectual disability and delays in motor growth, communication skills, language, social and adaptive behaviour. It is Hearing and vision impairments are also observed in subjects with this syndrome, as well as alterations of cardiac, endocrine and urinary systems and alterations at skin and skeletal level. Conclusions: Approximately 100 cases have been documented since 1981. This rare disease is the most common sub-telomeric-micro-deletion syndrome. In situ hybridization with fluorescence (FISH) and array-comparative genomic hybridization (CGH-array) are at present the two best diagnostic techniques. There is currently no effective medical treatment for this disease.

Patrones de hibridación del gen de fusión BCR/ABL1 en pacientes cubanos con leucemia / Hybridization patterns of BCR / ABL1 gen in cuban patients with leukemia

Introducción: la leucemia mieloide crónica (LMC) se caracteriza por la presencia de la translocación t(9,22) que resulta en la formación del gen de fusión BCR/ABL1. En ocasiones esta alteración genética puede asociarse con deleciones en secuencias del cromosoma 9 derivativo y otras variantes que no se observan con la citogenética convencional, pero pueden ser detectadas mediante la técnica de hibridación in situ por fluorescencia (FISH). Objetivo: describir los patrones de hibridación en pacientes positivos a la t(9;22) a partir de la introducción de la técnica de FISH para el estudio de las leucemias en Cuba. Métodos: se estudiaron muestras de sangre medular de 36 pacientes con LMC y ocho con leucemia linfoblástica aguda (LLA), en el Instituto de Hematología e Inmunología. Se empleó la sonda LSI BCR/ABL1 Dual Color Dual Fusion. Resultados: entre los pacientes con LMC, dos muestras resultaron no útiles para el diagnóstico y 18 fueron positivas para el BCR-ABL1, una de ellas mostró un patrón de hibridación atípico. Todas las muestras de pacientes con LLA resultaron negativas. En un paciente con impresión diagnóstica de LMC BCR-ABL1 negativo, se observó un patrón de señales que sugiere trisomía del cromosoma 9. Conclusiones: la incorporación de la técnica de FISH para el estudio del transcripto BCR/ABL1 en pacientes con LMC y LLA permitió detectar su presencia y la existencia de patrones de señales atípicos, los que pudieran no ser detectables mediante la citogenética convencional y tener significación pronóstica(AU)

Introduction: Chronic myeloid leukemia (CML) is characterized by the t(9;22) translocation resulting in the formation of BCR/ABL1 fusion gen. Sometimes this genetic alteration can be associated to deletions in sequences of derivative chromosome 9 and other variants detected by fluorescence in situ hybridization (FISH) technique. Objective: To describe hybridization patterns in patients positive to t(9;22) after the introduction of FISH at the leukemia study in Cuba. Methods: The bone marrow samples of 36 patients with diagnosis of CML and eight patients with acute lymphoblastic leukemia (ALL) were studied at the Cytogenetics Laboratory of the Institute of Hematology and Immunology. The BCR/ABL Dual Color Dual Fusion probe was used. Results: The sample of two CML patients were non-useful for diagnosis and 18 were t(9;22) positive, one with an atypical pattern of signals. All the ALL patients were negative. In one negative CML patient was observed a pattern of signals suggestive of trisomy 9. Conclusions: Incorporation of FISH for the BCR/ABL1 transcript study in CML and ALL patients allowed us to detect its presence and the existence of different patterns of signals which could be no detectable by conventional cytogenetic and could have prognostic significance(AU)

Hibridación in situ fluorescente: herramienta en el diagnóstico de las hemopatías malignas / Fluorescence in situ hybridization: diagnostic tool for hematological malignancies

Introducción: las neoplasias hematológicas tienen origen clonal y se caracterizan por presentar gran heterogeneidad genética. El desarrollo de la citogenética molecular a través de la hibridación in situ por fluorescencia (FISH, por su sigla en inglés) se convirtió en un avance importante en el diagnóstico citogenético de estas neoplasias. Objetivo: describir las alteraciones cromosómicas detectadas en pacientes con neoplasias hematológicas a partir de la introducción de esta técnica. Métodos: se realizó un estudio descriptivo de tipo transversal de pacientes con neoplasias hematológicas en el Laboratorio de Citogenética del Instituto de Hematología e Inmunología (IHI), en el período comprendido entre julio de 2014 y abril de 2015. Se utilizó la técnica de FISH con las sondas fluorescentes específicas. Resultados: se estudiaron 87 muestras correspondientes a diferentes tipos de neoplasias hematológicas. Con la sonda LSI BCR/ABL se observaron 18 casos positivos de leucemia mieloide crónica y los ocho pacientes con leucemia linfoide aguda fueron negativos. Se marcaron con sonda PML/RARα 17 muestras con diagnóstico de leucemia promielocítica: 10 fueron positivas. Se procesaron 8 muestras con la sonda LSI RUNX1/RUNX1T1, una resultó positiva. Dos muestras marcadas con sonda LSI RB1 (13q14) y una con LSI TP53 (17p13.1), resultaron negativas. se observó un caso positivo de deleción 7q31. Conclusiones: a pesar de que la muestra estudiada es pequeña, resulta importante reportar los primeros resultados como evidencia de la incorporación de la técnica de FISH en el IHI, lo que constituye una nueva herramienta para el diagnóstico, pronóstico y seguimiento de las neoplasias hematológicas(AU)

Introduction: hematological neoplasias have clonal origin and are characterized by great genetic heterogeneity. The development of molecular cytogenetic through fluorescence in situ hybridization (FISH) became a major advance in the cytogenetic diagnosis of these neoplasias. Aim: to describe chromosomal abnormalities detected in patients with hematological malignancies after the introduction of this technique. Methods: a descriptive cross-sectional study of patients with hematological malignancies was performed. Their bone marrow samples were processed at the Laboratory of Cytogenetics of the Institute of Hematology and Immunology, between July 2014 and April 2015. FISH technique was used along with various fluorescent probes. Results: 87 samples were studied. With LSI BCR / ABL probe, 18 samples were positive of chronic myeloid leukemia and 8 patients with diagnostic of acute lymphoblastic leukemia were negative. With PML/RARα probe 17 samples of patients with promyelocytic leukemia were labeled, 10 were positive. Eight samples were labeled with probe RUNX1 / RUNX1T1, one was positive. Two samples for LSI probes labeled RB1 (13q14) and one with LSI TP53 (17p13.1) were negative. One positive case 7q31 deletion was observed. Conclusions: despite the sample is small, we consider it important to report our first results as evidence of the incorporation of the FISH technique at the IHI, which constitutes a new tool for the diagnosis, prognosis and monitoring of hematological malignances(AU)

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.

HER2/neu status in breast cancer specimens: comparison of immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) methods / Estado del HER2/neu en especímenes con cáncer de mama: comparación entre los métodos de inmunohistoquímica (IHC) y fluorescencia de hibridación in situ (FISH)

HER2 amplification or overexpression is considered as disease outcome and a predictive marker of response to treatment in breast cancer. The present study aimed to compare the results of IHC and FISH for determining HER2 and to search the interpretational differences. Samples (n= 169), of which 31 were the paraffin blocks sent from outer centers, that underwent FISH analysis for HER-2 were included. Samples were re-reviewed by IHC in our laboratory. FISH test was negative in 131 (77.5%) and positive in 38 (22.5%). When those with previous IHC 0-1+ were re-reviewed, the results were found again 0-1+ and none of them was FISH positive. Inconsistency between re-reviewed IHC and previous IHC results was 25% for those with 2+ score and 11% for those with 3+ score. Consistency between IHC and FISH was 17% and 67% for previous IHC 2+ and 3+, respectively, whereas it was 23% and %75 for re-reviewed IHC 2+ and 3+, respectively. Whilst 79% of the samples evaluated as 2+ by the inexperienced pathologist were found to be 0-1+ on the re-review, all of them were FISH negative. According to our results, we suggest that samples with IHC 2+ should be re-reviewed by consulting with an experienced pathologist.

La amplificación o sobreexpresión de HER2 es un marcador predictivo de la respuesta al tratamiento en el cáncer de mama y es considerada como resultado de esta patología. El presente estudio tuvo como objetivo comparar los resultados de IHC y FISH para la determinación de HER2 y buscar diferencias de interpretación. Las muestras (n= 169), de las cuales 31 eran bloques de parafina, fueron enviadas desde centros externos y sometidas a análisis FISH para HER-2. Las muestras fueron revisadas en nuestro laboratorio con la prueba IHC. La prueba FISH resultó negativa en 131 casos (77,5%) y positiva en 38 (22,5%). Cuando se re-examinaron aquellos casos con resultados previos de IHC 0-1+, se encontró que los resultados fueron iguales (0-1+) y ninguno de ellos fue positivo para FISH. Se encontró inconsistencia entre los casos previos y las nuevas revisiones con IHC y fueron del 25% para aquellos casos con puntuación 2+ y del 11% para aquellos con 3+ de puntuación. La consistencia entre IHC y FISH fue del 17% y del 67% para casos previos analizados con IHC 2+ y 3+, respectivamente, mientras que fue de 23% y 75% para los reanalizados con IHC 2+ y 3+, respectivamente. Mientras que en el 79% de las muestras evaluadas con puntuación 2+ por patólogo inexperto resultaron ser 0-1 + con la nueva revisión, todos estos casos fueron FISH negativos. De acuerdo con nuestros resultados, sugerimos que las muestras con puntuación 2+ de IHC deben ser re-evaluadas por un patólogo experimentado.

Stability of XIST repression in relation to genomic imprinting following global genome demethylation in a human cell line

DNA methylation is essential in X chromosome inactivation and genomic imprinting, maintaining repression of XIST in the active X chromosome and monoallelic repression of imprinted genes. Disruption of the DNA methyltransferase genes DNMT1 and DNMT3B in the HCT116 cell line (DKO cells) leads to global DNA hypomethylation and biallelic expression of the imprinted gene IGF2 but does not lead to reactivation of XIST expression, suggesting that XIST repression is due to a more stable epigenetic mark than imprinting. To test this hypothesis, we induced acute hypomethylation in HCT116 cells by 5-aza-2′-deoxycytidine (5-aza-CdR) treatment (HCT116-5-aza-CdR) and compared that to DKO cells, evaluating DNA methylation by microarray and monitoring the expression of XIST and imprinted genes IGF2, H19, and PEG10. Whereas imprinted genes showed biallelic expression in HCT116-5-aza-CdR and DKO cells, the XIST locus was hypomethylated and weakly expressed only under acute hypomethylation conditions, indicating the importance of XIST repression in the active X to cell survival. Given that DNMT3A is the only active DNMT in DKO cells, it may be responsible for ensuring the repression of XIST in those cells. Taken together, our data suggest that XIST repression is more tightly controlled than genomic imprinting and, at least in part, is due to DNMT3A.

Characterization of a rare short arm heteromorphism of chromosome 22 in a girl with down-syndrome like facies.

Chromosomal heteromorphisms are described as interindividual variation of chromosomes without phenotypic consequence. Chromosomal polymorphisms detected include most regions of heterochromatin of chromosomes 1, 9, 16 and Y and the short arms of all acrocentric chromosomes. Here, we report a girl with Down‑syndrome such as facies and tremendously enlarged short arm of a chromosome 22. Fluorescence in situ hybridization (FISH) with a probe specific for all acrocentric short arms revealed that the enlargement p arms of the chromosome 22 in question contained exclusively heterochromatic material derived from an acrocentric short arm. Parental studies identified a maternal origin of this heteromorphism. Cryptic trisomy 21 of the Down‑syndrome critical region was excluded by a corresponding FISH‑probe. Here, we report, to the best of our knowledge, largest ever seen chromosome 22 short arm, being ~×1.5 larger than the normal long arm.

El uso de alteraciones genéticas en la estratificación por riesgo del mieloma múltiple / Genetic tools for risk-stratification in multiple myeloma

Los estudios genéticos han alcanzado un papel central en el estudio del mieloma múltiple (MM), al convertirse en un componente crítico en la estratificación basada en el riesgo de la enfermedad. Se han hecho grandes esfuerzos para identificar cambios genéticos que puedan predecir el resultado clínico e incluirlos en la práctica clínica diaria. La hibridización in situ fluorescente (FISH) es todavía la técnica genética más utilizada en la práctica clínica, mayormente debido a su sencilla implementación y su simplicidad para el análisis de datos. El advenimiento de la genómica (hibridización genómica comparativa, secuenciación exónica o genómica completa) y del transcriptoma de alta resolución (perfiles de expresión de genes - GEP y secuenciación de ARNm) proveen un análisis exhaustivo de los ya definidos factores pronósticos genéticos y son herramientas útiles para la identificación de potenciales nuevos marcadores pronósticos de enfermedad en el clon tumoral de MM. Más aún, GEP ha sido exitosamente implementado en MM como una herramienta de estratificación de riesgo, siendo la de mayor poder de discriminación de resultados. De todas maneras, algunos aspectos técnicos y logísticos complejos (necesidad de una elevada purificación del clon tumoral, costo de los ensayos y complejidad en los análisis de los datos) deben ser considerados antes de la incorporación definitiva de estas tecnologías de alto rendimiento dentro de los ensayos clínicos de rutina. Hasta entonces, FISH continúa siendo la herramienta estándar para la detección de anormalidades genéticas y de valoración pronóstico de enfermedad.

Genetic studies have a central role in the study of multiple myeloma (MM), as they become a critical component in the risk-based stratification of the disease. Significant efforts have been made to identify genetic changes and signatures that can predict clinical outcome and include them in the routine clinical care. Fluorescence in situ hybridization (FISH) still remains the most used genetic technique in clinical practice, mostly due to its very straightforward implementation and the simplicity of data analysis. The advent of high-resolution genomics (i.e. array CGH, exome and whole genome sequencing) and transcriptomics tests (i.e. gene expression profiling - GEP, and mRNA sequencing) provide a comprehensive analysis of the already defined genetic prognostic factors and are helpful tools for the identification of potential novel disease markers on the MM tumor clone. Indeed, GEP has been successfully implemented in MM as a risk-stratification tool, holding the greatest power in outcome discrimination. Nevertheless, some technical and logistic intricacies (need of a highly purified tumor clone, cost of the assay and complexity of data analysis) need to be considered before the definitive incorporation of high-throughput technologies in routine clinical tests. Until then, FISH remains the standard tool for genomic abnormality detection and disease prognostication.

Rapid-prenatal diagnosis through fluorescence in situ hybridization for preventing aneuploidy related birth defects.

BACKGROUND AND OBJECTIVE: Women with high-risk pregnancies are offered prenatal diagnosis through amniocentesis for cytogenetic analysis of fetal cells. The aim of this study was to evaluate the effectiveness of the rapid fluorescence in situ hybridization (FISH) technique for detecting numerical aberrations of chromosomes 13, 21, 18, X and Y in high-risk pregnancies in an Indian scenario. MATERIALS AND METHODS: A total of 163 samples were received for a FISH and/or a full karyotype for prenatal diagnosis from high-risk pregnancies. In 116 samples both conventional culture techniques for getting karyotype through G-banding techniques were applied in conjunction to FISH test using the AneuVysion kit (Abbott Molecular, Inc.), following standard recommended protocol to compare the both the techniques in our setup. RESULTS: Out of 116 patients, we got 96 normal for the five major chromosome abnormality and seven patients were found to be abnormal (04 trisomy 21, 02 monosomy X, and 01 trisomy 13) and all the FISH results correlated with conventional cytogenetics. To summarize the results of total 163 patients for the major chromosomal abnormalities analyzed by both/or cytogenetics and FISH there were 140 (86%) normal, 9 (6%) cases were abnormal and another 4 (2.5%) cases were suspicious mosaic and 10 (6%) cases of culture failure. The diagnostic detection rate with FISH in 116 patients was 97.5%. There were no false-positive and false-negative autosomal or sex chromosomal results, within our established criteria for reporting FISH signals. CONCLUSION: Rapid FISH is a reliable and prompt method for detecting numerical chromosomal aberrations and has now been implemented as a routine diagnostic procedure for detection of fetal aneuploidy in India.