Fluorescence in situ hybridization in plants: recent developments and future applications.

Fluorescence in situ hybridization (FISH) was developed more than 30 years ago and has been the most paradigm-changing technique in cytogenetic research. FISH has been used to answer questions related to structure, mutation, and evolution of not only individual chromosomes but also entire genomes. FISH has served as an important tool for chromosome identification in many plant species. This review intends to summarize and discuss key technical development and applications of FISH in plants since 2006. The most significant recent advance of FISH is the development and application of probes based on synthetic oligonucleotides (oligos). Oligos specific to a repetitive DNA sequence, to a specific chromosomal region, or to an entire chromosome can be computationally identified, synthesized in parallel, and fluorescently labeled. Oligo probes designed from conserved DNA sequences from one species can be used among genetically related species, allowing comparative cytogenetic mapping of these species. The advances with synthetic oligo probes will significantly expand the applications of FISH especially in non-model plant species. Recent achievements and future applications of FISH and oligo-FISH are discussed.

Toward High-Throughput and Multiplexed Imaging of Genome Organization.

Dr. Eric Joyce from the Department of Genetics at the University of Pennsylvania was awarded The President's Innovation award at the annual Society of Biomolecular Imaging and Informatics meeting held in Boston, September 2016. Chromosome interactions are a fundamental aspect of nuclear organization that can activate and silence genes or even direct chromosome rearrangements. However, the molecular mechanisms underlying how chromosomal segments find each other and form stable interactions within cells remain unknown. To address this gap, we have recently developed two technologies that use fluorescent in situ hybridization (FISH) to interrogate chromosome positioning at single-cell resolution. The first is a technology for high-throughput FISH, and the other, called Oligopaints, is a new type of probe that reduces the cost and increases the resolution of FISH. Here, I review our use of these two technologies to uncover and characterize the molecular mechanisms that govern chromosome pairing in Drosophila. I further describe how these methods should benefit a broad spectrum of research fields, including those focusing on chromatin looping, compaction, replication, homologous recombination, and DNA repair.

Common Fluorescence In Situ Hybridization Applications in Cytology.

CONTEXT: - Fluorescence in situ hybridization (FISH) is a well-established method for detection of genomic aberrations in diagnostic, prognostic, and predictive marker testing. OBJECTIVE: - To review common applications of FISH in cytology. DATA SOURCES: - The published literature was reviewed. CONCLUSIONS: - Cytology is particularly well suited for all kinds of FISH applications, which is highlighted in respiratory tract cytology with an increasing demand for predictive FISH testing in lung cancer. Fluorescence in situ hybridization is the gold standard for detection of predictive anaplastic lymphoma kinase gene (ALK) rearrangements, and the same evaluation criteria as in histology apply to cytology. Several other gene rearrangements, including ROS proto-oncogene 1 receptor tyrosine kinase (ROS1), are becoming clinically important and share the same underlining cytogenetic mechanisms with ALK. MET amplification is one of the most common mechanisms of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors and can be targeted by crizotinib. As genomic aberrations are a hallmark of malignant cells, FISH is a valuable objective ancillary diagnostic tool. In urinary tract cytology, atypical urothelial cells equivocal for malignancy are a common diagnostic dilemma and multitarget FISH can help clarify such cells. Diagnosis of malignant mesothelioma remains one of the most challenging fields in effusion cytology, and ancillary FISH is useful in establishing the diagnosis. Fluorescence in situ hybridization is a morphology-based technique, and the prerequisite for reliable FISH results is a targeted evaluation of the cells in question (eg, cancer or atypical cells). Cytopathologists and cytotechnicians should therefore be involved in molecular testing in order to select the best material and to provide their morphologic expertise.

Recent advances of genomic testing in perinatal medicine.

Rapid progress in genomic medicine in recent years has made it possible to diagnose subtle genetic abnormalities in a clinical setting on routine basis. This has allowed for detailed genotype-phenotype correlations and the identification of the genetic basis of many congenital anomalies. In addition to the availability of chromosomal microarray analysis, exome and whole-genome sequencing on pre- and postnatal samples of cell-free DNA has revolutionized the field of prenatal diagnosis. Incorporation of these technologies in perinatal pathology is bound to play a major role in coming years. In this communication, we briefly present the current experience with use of classical chromosome analysis, fluorescence in situ hybridization, and microarray testing, development of whole-genome analysis by next-generation sequencing technology, offer a detailed review of the history and current status of non-invasive prenatal testing using cell-free DNA, and discuss the advents of these new genomic technologies in perinatal medicine.

New developments in comet-FISH.

The comet assay combined with fluorescence in-situ hybridisation (FISH) is a powerful technique for comparative analyses of damage induction and repair in genomes and in specific DNA sequences within single cells. Recent advances in the methodology of comet-FISH will be considered here, with particular attention to the design and generation of fluorescent probes. In general, all the approaches must fulfil a few basic requirements: the probes should be no longer than ~300 nucleotides in length (single or double stranded) to be able to penetrate the gel in which the target genomic DNA is embedded, they should be sequence-specific, and their signal should be detectable and distinct from the background fluorescence and the dye used to stain the DNA.

Fine needle aspiration: past, current practice and recent developments.

Fine needle aspiration (FNA) is a diagnostic technique that has become widely used. The procedure may be performed by interventional radiologists, endoscopists, pathologists and cytotechnologists; diagnostic interpretation of FNA samples is performed by pathologists and cytotechnologists. I provide here an introduction to the technique and applications of FNA with a review of current practice parameters and recent developments in the molecular application of FNA.

La hibridación in situ fluorescente en la predicción de recurrencia del carcinoma urotelial / Fluorescent in situ Hybridization as a Predictor of Relapse in Urotelial Carcinoma

Objetivo: Evaluar la utilidad del estudio de alteraciones cromosómicas mediante hibridación in situ fluorescente en una serie de pacientes diagnosticados de carcinoma urotelial con un seguimiento mínimo de 24 meses, y analizar su posible efecto anticipador. Material y métodos: La serie global incluye 338 muestras procedentes de 98 pacientes con 84 episodios de carcinoma urotelial. Para evaluar la capacidad de predicción del test se estudió un subgrupo de 24 pacientes que presentaron como mínimo una recurrencia a lo largo del seguimiento (serie de recurrencia). Se consideraron 3 categorías (episodio coherente positivo, episodio coherente negativo y episodio no coherente) en función de la relación entre los resultados de la hibridación in situ fluorescente del estudio concomitante al nuevo episodio y las muestras precedentes. Resultados: La hibridación in situ fluorescente presentó mayor sensibilidad independientemente del grado, valor predictivo negativo y exactitud, mientras que la especificidad y el valor predictivo positivo fueron superiores para la citología convencional. En la serie de recurrencia 19/29 episodios resultaron coherentes, 11/19 fueron coherentes positivos, todos con carcinoma urotelial de alto grado, y 8/19 coherentes negativos, la mayoría de bajo grado. Conclusiones: La hibridación in situ fluorescente muestra una alta sensibilidad en un seguimiento de 24 meses, y es capaz de predecir recurrencias, especialmente en casos de alto grado. Nuestros datos demuestran también la existencia de carcinomas uroteliales sin alteraciones cromosómicas detectables con la metodología actualmente disponible. Los resultados apoyan un seguimiento multidisciplinar con la utilización combinada de la hibridación in situ fluorescente, citología y cistoscopia (AU)

Objective: To assess the value of the study of chromosomal alterations by fluorescent in situ hybridization in a series of patients diagnosed of urothelial carcinoma and a minimum follow up of twenty four months, as well as evaluate its putative predictive potential. Material and methods: The overall series includes 338 samples from 98 patients with 84 episodes of urothelial carcinoma. A subgroup of 24 patients who had at least one recurrence during the follow up was used to evaluate the predictive potential of the test. Three categories were considered (positive coherent episode, negative coherent episode, and incoherent episode) depending on the relationship between the fluorescent in situ hybridization result in the concomitant study of the new episode and those of the preceding samples. Results: Fluorescent in situ hybridization showed higher sensitivity regardless of grade, negative predictive value and accuracy, while specificity and positive predictive value were superior with conventional cytology. In the recurrence, series 19/29 episodes were coherent, 11/19 were positive coherent with urothelial carcinoma all high grade and 8/19 negative coherent, most low grade. Conclusions: Fluorescent in situ hybridization test shows good sensitivity during a follow up of twenty four months and is able to predict recurrence, especially in cases of high grade. Our data demonstrate the existence of urothelial carcinomas without detectable chromosomal abnormalities by currently available methodology. The results support a multidisciplinary follow up combining fluorescent in situ hybridization, cytology and cystoscopy (AU)

Diagnóstico de aneuplodias en células en interfase de líquido amniótico mediante hibridación in situ fluorescente. Concordancia con el cariotipo / Diagnosis of aneuploidy in interphase cells of amniotic fluid by fluorescence in situ hybridization. Concordance with the karyotype

Introducción. En los últimos años la aplicación de la hibridación in situ fluorescente (FISH) permite el diagnóstico precoz de aneuploidias. El objetivo de este estudio es el análisis descriptivo mediante FISH de los líquidos amnióticos procesados en el laboratorio y la concordancia con el cariotipo. Material y métodos. Análisis de 821 muestras de líquidos amnióticos (enero 2009 a diciembre 2010) remitidas por Medicina Fetal desde la semana 13 a 36 de gestación para estudio prenatal de aneuploidias, (kit Aneuvysion) con sondas centroméricas para los cromosomas X, Y y 18, y locus específicas para los cromosomas 13 y 21. El estudio se completa con el cariotipo mediante método de bandeo G. Resultados. De las 821 muestras, 776 (94,52%) fueron normales y 45 (5,48%) presentaron aneuploidias: en 22 casos (48,88%) el sexo cromosómico del feto fue masculino, en las 23 restantes (51,12%) femenino. La cromosopatía más frecuente fue la trisomía 21 (19 casos en fetos masculinos y 11 femeninos), la de menor presentación fue la trisomía 13 (2 casos) que representa el 0,24% del total de los líquidos amnióticos procesados. En todos los casos, la concordancia con el cariotipo fue del 100%. Conclusiones. El estudio de aneuploidias mediante FISH en núcleos en interfase en líquido amniótico permite un diagnóstico prenatal rápido de las principales cromosomopatías, siendo la trisomía 21 la más frecuentemente detectada. Los resultados del FISH coincidieron en el 100% con el cariotipo, gold estándar en el diagnóstico prenatal de cromosomopatías (AU)

Background. The application of fluorescence in situ hybridization (FISH) techniques in the last few years has led to the prenatal diagnosis of aneuploidies. The objective of this investigation was a descriptive analysis of amniotic fluids processed in the laboratory using FISH and the agreement with the karyotype. Material and methods. A total of 821 amniotic fluid samples (January 2009 to December 2010) at gestational ages 13 to 36 weeks, from Fetal Medicine Unit for prenatal testing for aneuploidies (Aneuvysion kit) with centromeric probes for chromosomes X,Y and 18, and locus specific for chromosomes 13 and 21. The study was complemented by the karyotype by G-banding method. Results. Of the 821 samples, 776 (94.52%) were normal and 45 (5.48%) had aneuploidy: in 22 cases (48.88%) the chromosomal sex of the foetus was male, in the remaining 23 (51.12%) female. The most common chromosomal abnormality detected was trisomy 21 (19 cases in males and 11 cases in female foetuses), the lowest performance was the trisomy 13 (2 cases) representing 0.24% of total processed amniotic fluids. In all cases, the concordance with the karyotype was 100%. Conclusions. The study of aneuploidy by FISH of interphase nuclei present in the amniotic fluid enables rapid prenatal diagnosis of major chromosomal abnormalities, trisomy 21 was more frequently detected. FISH results in 100% agreed with the karyotype, the gold standard in prenatal diagnosis of chromosomal abnormalities (AU)

A proposal for improving multicolor FISH sensitivity in the diagnosis of malignant melanoma using new combined criteria.

Fluorescence in situ hybridization (FISH) for the diagnosis of melanoma makes use of specific fluorescent probes to detect selected chromosomal alterations on paraffin-embedded tissue samples. To date, interpretation of FISH data has been based on numerical values generated by 2 different computational algorithms that of Abbott and that of Gerami. To further evaluate the value of FISH in the diagnosis of malignant melanoma, we selected 163 clinically and histologically unequivocal cases of malignant melanoma in a cohort of 575 melanocytic tumors and analyzed FISH data using the criteria of Abbott, Gerami, and new combined criteria. Depending on the used criteria, FISH was positive in the unequivocal malignant melanoma in 69.3% (113/163) of cases using the Abbott criteria, 74.2% (121/163) of cases using the Gerami criteria, and 82.2% (134/163) of cases using the combined criteria of Abbott and Gerami. Although use of all 3 criteria was associated with 100% FISH negativity in a cohort of 30 unequivocal benign melanocytic nevi, use of the combined criteria revealed more FISH-positive cases in ambiguous benign melanocytic lesions than the criteria of Abbott or Gerami alone: Abbott, 125 of 367; Gerami, 146 of 367; combined, 161 of 367. Furthermore, we show that 66% (8/12) of FISH-negative cases of unequivocal melanoma are positive when analyzed by array comparative genomic hybridization (aCGH), demonstrating that false-negative results remain despite the usage of the combined criteria for evaluation of FISH data. In these 8 FISH-negative aCGH-positive cases, copy number alterations were often located on chromosomes 9p, a chromosomal locus that is not targeted by the FISH probes currently used. In conclusion, the existing criteria for the evaluation of multicolor melanocytic FISH are limited by a nonnegligeable rate of false negativity that can be reduced by using newly proposed combined criteria but at the cost of increased detection of FISH positivity in ambiguous benign melanocytic lesions.

New trends in fluorescence in situ hybridization for identification and functional analyses of microbes.

Fluorescence in situ hybridization (FISH) has become an indispensable tool for rapid and direct single-cell identification of microbes by detecting signature regions in their rRNA molecules. Recent advances in this field include new web-based tools for assisting probe design and optimization of experimental conditions, easy-to-implement signal amplification strategies, innovative multiplexing approaches, and the combination of FISH with transmission electron microscopy or extracellular staining techniques. Further emerging developments focus on sorting FISH-identified cells for subsequent single-cell genomics and on the direct detection of specific genes within single microbial cells by advanced FISH techniques employing various strategies for massive signal amplification.

[Chromosome territories in the interphase nucleus in normal or pathological condition].

The non-random arrangement of chromosomes in the interphase nucleus was observed for the first time in the late XIX century. However, considerable progress in studying chromosome territories became possible only in the end of the XX century mainly due to advances in microscopy and molecular biology. At present, chromosome territories are believed to play an important role in epigenetic regulation of genome activity during various cell processes including but not limited to cell cycle, differentiation, stress response. 3D structure of genome also plays an important role in pathogenesis of various hereditary diseases and cancer. This article describes main provisions of the chromosome territory theory and current trends toward further development of human genetics based on the new knowledge about the role of chromosome territories.

De la citogenética convencional al análisis por micromatrices. Cincuenta años del cromosoma Filadelfia / From conventional cytogenetics to microarrays. Fifty years of Philadelphia chromosome

Desde la descripción, en el año 1960, del cromosoma Filadelfia como una alteración asociada con la leucemia mieloide crónica se han descrito una multitud de alteraciones citogenéticas en los enfermos con hemopatías malignas, de manera que, en la actualidad, la realización de estos estudios es imprescindible en estas enfermedades. La presencia de cambios citogenéticos no solo contribuye a un mejor diagnóstico y clasificación de las leucemias y de los linfomas, sino que es un factor pronóstico de primer nivel. Por esto, la clasificación de la Organización Mundial de la Salud las ha incluido como parte fundamental del diagnóstico de las hemopatías malignas. El desarrollo de la hibridación «in situ» fluorescente y, más recientemente, de las micromatrices ha contribuido a un mejor conocimiento de estas enfermedades, por lo que se consideran un complemento de los estudios citogenéticos. Los cambios citogenéticos observados en estos enfermos son, en ocasiones, una pieza clave en el enfoque terapéutico (AU)

In 1960 Ph-chromosome was found associated with the presence of chronic myelogenous leukemia. In these 50 years an increasing number of cytogenetic abnormalities have been found associated with hematological malignancies. The presence of these abnormalities is not only important for the diagnosis of the patient, but it also contributes to the prognosis of patients with leukemia or lymphoma. For this reason the WHO classification of hematological disease has included these studies for the correct characterization of leukemias and lymphomas. In addition, the use of FISH and micromatrix methodologies have refined the genetic lesions present in these malignancies. The cytogenetic changes observed also provide further information in relation to the therapy (AU)

PGS-FISH in reproductive medicine and perspective directions for improvement: a systematic review.

INTRODUCTION: Embryo selection can be carried out via morphological criteria or by using genetic studies based on Preimplantation Genetic Screening. In the present study, we evaluate the clinical validity of Preimplantation Genetic Screening with fluorescence in situ hybridization (PGS-FISH) compared with morphological embryo criteria. MATERIAL AND METHODS: A systematic review was made of the bibliography, with the following goals: firstly, to determine the prevalence of embryo chromosome alteration in clinical situations in which the PGS-FISH technique has been used; secondly, to calculate the statistics of diagnostic efficiency (negative Likelihood Ratio), using 2 × 2 tables, derived from PGS-FISH. The results obtained were compared with those obtained from embryo morphology. We calculated the probability of transferring at least one chromosome-normal embryo when it was selected using either morphological criteria or PGS-FISH, and considered what diagnostic performance should be expected of an embryo selection test with respect to achieving greater clinical validity than that obtained from embryo morphology. RESULTS: After an embryo morphology selection that produced a negative result (normal morphology), the likelihood of embryo aneuploidies was found to range from a pre-test value of 65% (prevalence of embryo chromosome alteration registered in all the study groups) to a post-test value of 55% (Confidence interval: 50-61), while after PGS-FISH with a negative result (euploid), the post-test probability was 42% (Confidence interval: 35-49) (p < 0.05). The probability of transferring at least one euploid embryo was the same whether 3 embryos were selected according to morphological criteria or whether 2, selected by PGS-FISH, were transferred. Any embryo selection test, if it is to provide greater clinical validity than embryo morphology, must present a LR-value of 0.40 (Confidence interval: 0.32-0.51) in single embryo transfer, and 0.06 (CI: 0.05-0.07) in double embryo transfer. DISCUSSION: With currently available technology, and taking into account the number of embryos to be transferred, the clinical validity of PGS-FISH, although superior to that of morphological criteria, does not appear to be clinically relevant.

Consenso de la Sociedad Española de Anatomía Patológica (SEAP) y de la Sociedad Española de Oncología Médica (SEOM) sobre la determinación de HER2 en el carcinoma gástrico / HER2 evaluation in gastric carcinoma: A consensus study by the Spanish Society of Pathology (SEAP) and the Spanish Society of Medical Oncology (SEOM)

La identificación de los carcinomas gástricos avanzados con alteraciones de HER2 es esencial en la práctica clínica diaria, ya que estas neoplasias requieren un tratamiento específico con trastuzumab. Por estos motivos, patólogos y oncólogos expertos en carcinoma gástrico y en la determinación de HER2, en representación de las sociedades respectivas (SEAP y SEOM), han trabajado para debatir y consensuar las recomendaciones nacionales de determinación de HER2 en los carcinomas gástricos. Estas recomendaciones se basan no sólo en la experiencia de los participantes en el consenso, sino también en la experiencia internacional publicada. En este consenso se muestran los requisitos mínimos que un laboratorio de anatomía patológica debe cumplir para garantizar la adecuada determinación de HER2 en la práctica diaria. Los laboratorios que carezcan de los estándares mínimos expuestos en esta guía deberían trabajar en alcanzarlo(AU)

The identification of HER2 alterations in advanced gastric carcinomas is critically important in daily clinical practice as such neoplasms require specific treatment with Trastuzumab. For this reason, expert pathologists and oncologists have agreed on national guidelines for HER2 testing in gastric carcinomas. The guidelines are based on the experience of the participants and pertinent recent international publications. They outline the minimum requirements for the Pathology Laboratory in order to guarantee satisfactory routine HER2 testing. The guidelines recommend that any laboratory not fulfilling such requirements make the adjustments necessary for compliance(AU)

Out of the darkness and into the light: bright field in situ hybridisation for delineation of ERBB2 (HER2) status in breast carcinoma.

Assessment of ERBB2 (HER2) status in breast carcinomas has become critical in determining response to the humanised monoclonal antibody trastuzumab. The current joint College of American Pathologists and the American Society of Clinical Oncology guidelines for the evaluation of HER2 status in breast carcinoma involve testing by immunohistochemistry and fluorescence in situ hybridisation (FISH). However, neither of these modalities is without limitations. Novel bright field in situ hybridisation techniques continue to provide viable alternatives to FISH testing. While these techniques are not limited to evaluation of the HER2 gene, the extensive number of studies comparing bright field in situ techniques with other methods of assessing HER2 status allow a robust evaluation of this approach. Analysis of the literature demonstrates that, when used to assess HER2 gene status, bright field in situ hybridisation demonstrates excellent concordance with FISH results. The average percentage agreement in an informal analysis of studies comparing HER2 amplification by chromogenic in situ hybridisation with FISH was 96% (SD 4%); kappa coefficients ranged from 0.76 to 1.0. Although a much smaller number of studies are available for review, similar levels of concordance have been reported in studies comparing HER2 amplification by methods employing metallography (silver in situ hybridisation) with FISH. A summary of the advancements in bright field in situ hybridisation, with focus on those techniques with clinical applications of interest to the practicing pathologist, is presented.

Recent advances in rice genome and chromosome structure research by fluorescence in situ hybridization (FISH).

Fluorescence in situ hybridization (FISH) is an effective method for the physical mapping of genes and repetitive DNA sequences on chromosomes. Physical mapping of unique nucleotide sequences on specific rice chromosome regions was performed using a combination of chromosome identification and highly sensitive FISH. Increases in the detection sensitivity of smaller DNA sequences and improvements in spatial resolution have ushered in a new phase in FISH technology. Thus, it is now possible to perform in situ hybridization on somatic chromosomes, pachytene chromosomes, and even on extended DNA fibers (EDFs). Pachytene-FISH allows the integration of genetic linkage maps and quantitative chromosome maps. Visualization methods using FISH can reveal the spatial organization of the centromere, heterochromatin/euchromatin, and the terminal structures of rice chromosomes. Furthermore, EDF-FISH and the DNA combing technique can resolve a spatial distance of 1 kb between adjacent DNA sequences, and the detection of even a 300-bp target is now feasible. The copy numbers of various repetitive sequences and the sizes of various DNA molecules were quantitatively measured using the molecular combing technique. This review describes the significance of these advances in molecular cytology in rice and discusses future applications in plant studies using visualization techniques.

Prokaryotic community structure in algal photosynthetic biofilms from extreme acidic streams in Río Tinto (Huelva, Spain)

Four algal photosynthetic biofilms were collected from the Río Tinto (SW Spain) at four localities: AG, Euglena and Pinnularia biofilms; ANG, Chlorella and Pinnularia biofilms; RI, Cyanidium and Dunaliella biofilms; and CEM, Cyanidium, Euglena and Pinnularia biofilms. Community composition and structure were studied by a polyphasic approach consisting of 16S rRNA analysis, scanning electron microscopy by back-scattered electron detection mode (SEM-BSE), and fluorescence in-situ hybridization (FISH). Acidophilic prokaryotes associated with algal photosynthetic biofilms included sequences related to the Alpha-, Beta-, and Gammaproteobacteria (phylum Proteobacteria) and to the phyla Nitrospira, Actinobacteria, Acidobacteria and Firmicutes. Sequences from the Archaea domain were also identified. No more than seven distinct lineages were detected in any biofilm, except for those from RI, which contained fewer groups of Bacteria. Prokaryotic communities of the thinnest algal photosynthetic biofilms (-100 microm) were more related to those in the water column, including Leptospirillum populations. In general, thick biofilms (200 microm) generate microniches that could facilitate the development of less-adapted microorganisms (coming from the surrounding environment) to extreme conditions, thus resulting in a more diverse prokaryotic biofilm (AU)

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Fifty years of cytogenetics: a parallel view of the evolution of cytogenetics and genotoxicology.

A parallelism exists between human cytogenetics and cytogenetic toxicology. The breakthroughs, mostly coming from and used in clinical genetics, are widely used in genetic toxicology. The birth of human cytogenetics occurred in 1956 when it was published that the diploid number of chromosomes in humans is 46. The first stage in chromosome-induced mutagenesis began in 1938 when Sax published the effects of X-rays on the chromosomes of Drosophila. In 1959, the cytogenetic anomalies for Down, Klinefelter, and Turner syndromes were described, and parallelly in 1960, the first publication on chromosomal aberrations in man caused by ionizing radiation appeared. The cytogenetic analysis of chromosomal aberrations in cell cultures is considered one of the primary methods to evaluate induced mutagenesis. At the end of the 1960s, banding techniques allowed chromosomes to be individually identified, in parallel, the sister chromatid exchange analysis technology was described. Another milestone in the history of induced mutagenesis was the discovery that mutagenic agents were able to alter chromosomal division and segregation in gonads inducing meiotic nondisjunction. Here we review new approaches and applications such as biological dosimetry, translocation scoring using FISH, and micronucleus test. Chromosomal aberrations and micronucleus test are now effective cytogenetic biomarkers of early effect used as cancer predictors. Human cytogenetics has proven to be effective over its 50-year lifespan and, although each new technique that has appeared seemed to announce its end, the fact is that the current state of cytogenetics is in reality a collection of techniques that, while common, are cheap, fast, and wide-ranging. Therefore, in genotoxicology, they continue to be useful to identify mutagenic agents as well as to evaluate and analyze exposed populations.