**2. Cytogenetic technic**

Cytogenetic study plays a crucial role on haematology, its the main outil for making diagnosis for almost all haematological malignancies, and its have an important impact prognosis for those diseases, and cytogenetic abnormalities are included on almost all prognosis score and risk stratifications for haematological neoplasms.

The past several years' remarkable efforts were deployed for better understanding of genetics and genome biology, many new technologies were developed, and the old technic saw improved their sensibility and specificity.

Veritable revolution was seen thanks to NGS, this technic offers possibility of broad analysis of a genome by whole-genome sequencing (WGS), exome sequencing, transcriptome sequencing, and epigenomics [5].

#### **2.1 Conventional cytogenetic**

Cytogenetic analyse in hematologicl neoplasms is performed by bone marrow aspiration in sterile way with heparine filled probes.

Sometimes, katyotype can be realised by peripheral blood.

The Celle of aspirated bonne marrow are cultured in vitro, then microscopic slides with metaphases chromosomes and/or interphase nuclei is performed.

Karyotype needs many metaphases cell (20 to 30) to be significatif, so its required time [2].

Conventional cytogenetics still be the most frequently ordered genetic test for various leukaemias, most prominently chronic myelogenous leukaemia (CML) in a resource limited situation.

#### **2.2 Fluorescence in situ hybridization (FISH)**

FISH is the best alternative to karyotype, it is rapid technic, with high level of specificity and sensibility. It can be realised from bone marrow or peripheral blood, it can also be performed from fixed and sectioned tissue [3].

FISH constitues a big step for studying somatic chromosomal mosaicism and molecular cytogenetic detection of chromosomal variations in interphase nuclei [6, 7].

FISH is a molecular cytogenetic technique, it identifies chromosomal abnormalities using molecular technology.

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abnormalities.

*Haematological Malignancies: Overview of the Recent Progresses in Genetics*

Technic of FISH is based on A DNA probe is tagged with a fluorescent marker. The probe and target DNA are denatured, and the probe is allowed to hybridise with the target. The fluorescent tag is then detected with a fluorescent microscope.

PCR is a technique that involves amplification of a desired segment of DNA by using primers, nucleotides and enzymes like reverse transcriptase and DNA polymerases. It represents the most used molecular technique on haematology. Different types of PCRs exist. Reverse transcriptase PCR (RT-PCR), Real time PCR (RQ-PCR). In clinical practice RQ PCR is commonly used for viral copies detection and specific gene detection like Bcr-abl and PML-RARA for assessment of treatment response [1] new technique was developted: Digital PCR it s used for DNA/RNA detection and quantification. It is emerging as an alternative to conventional RQ-PCR for quantification and low abundance mutation detection [8].

PCR have many applications in hematologic malignancies include. it s used for detection of fusion genes and mutations. Its also performed for analysing of post transplant chimerism, and can be realised for determination of lymphoid clonality.

Microarray based testing such as array comparative genomic hybridization (CGH) and single nucleotide polymorphisms (SNP) arrays are now more used in

The copy numbers of DNA sequences in the test and reference samples are quantified by assessment of relative fluorescence intensities detected by digital

This technique is based on DNA microarray which utilises plates which have

At present availability of GEP is limited to few research centers only limiting its

Over the past few years, an important increasing of the use of NGS on haematology have been shown, new platforms are available and are very helpful to identify

Next-generation sequencing (NGS) encompasses several different methodologies that allow the investigation of genomics, transcriptomics and epigenomics [4]. Application of NGS in hematologic malignancies has confirmed presence of a lot of mutation of certain genes like TP53, ATM, RAS etc. the inconvenient for NGS, its the cost, this technic still expensive and can not be used on large spectre today

Haematological neoplasms benefits from progress of biological technology, the use of new platforms helps to approve the performance of identification of genetic

various complementary genetic sequence covalently attached to them.

the genetic basis of haematological neoplasms and genome biology.

routine diagnostics for haematological malignancies.

*DOI: http://dx.doi.org/10.5772/intechopen.96913*

**2.3 Polymerase chain reaction (PCR)**

**2.4 Genome-wide arrays**

**2.5 Gene expression profiling**

wide use in clinical practice.

**2.6 New generation sequencing**

especially for limited resource's country.

**3. Haematological malignancies applications**

imaging systems.

Technic of FISH is based on A DNA probe is tagged with a fluorescent marker. The probe and target DNA are denatured, and the probe is allowed to hybridise with the target. The fluorescent tag is then detected with a fluorescent microscope.
