Journal of the Association of Genetic Technologists最新文献

Objectives: T-cell prolymphocytic leukemia, or T-PLL, is an extremely rare and highly metastatic neoplasm characterized by proliferating mature T-cells and genetic aberrations that often involve chromosome 14. While T-PLL is commonly accompanied by a complex karyotype, there is little analysis on such cases in existing literature and thorough discussions of the less "characteristic" cytogenetic mutations are particularly lacking. We present a case study of a 68-year-old male T-PLL patient with marked leukocytosis and a history of T-cell lymphoproliferative disorder. Chromosomal analysis revealed a complex karyotype that included a translocation of both copies of chromosome 14, rearrangements on 9p and 5p, isochromosome 8, deletion 11q, and monosomy 17. Molecular cytogenetic analysis indicated a rearrangement of TRD (14q11.2), loss of the ATM and CDKN2A signals, and gains of the RELN, TES and MYC signals. Many of these mutations have strongly corresponded to poor prognoses in patients with T-PLL and other leukemias, especially when appearing concurrently. However, there are still profound knowledge gaps in our understanding of many genetic aberrations and the significance of marker chromosomes in the context of T-PLL. Considering the lack of consensus on the improvement of patient outcomes in the past two decades as well as the frequency of a complex karyotype in T-PLL, this case study highlights the critical need of continued research efforts in profiling complex cases to provide potential avenues for novel therapeutic targets for T-PLL patients.

Objectives: Acute myeloid leukemia (AML) is a heterogeneous malignancy of precursor myeloid cells. Identification and understanding of chromosomal abnormalities are key diagnostic and prognostic factors for patients with AML, as they play an important role in risk stratification algorithms. Hypodiploidy, a rare cytogenetic abnormality resulting in a karyotype with fewer than 46 chromosomes, is a rare finding in AML. It is often characterized by the involvement of chromosomes 5, 7, and/or 17, as well as the structural aberration t(8;21)(q22;q22), which is frequently accompanied by the clonal loss of a sex chromosome. Modal number (MN) has been shown to play a role in prognosis, with lower values associated with poorer survival. While hypodiploidy is frequently discussed within the context of acute lymphoblastic leukemia (ALL), its impact has garnered little relevance within AML studies. In this review, we aim to elucidate the characteristics of hypodiploidy in AML, investigate its prognostic significance, and explore its relationship with monosomal karyotypes, a more favored method of risk stratification.

Objectives: Acute myeloid leukemia (AML) is a clonal disorder of myeloid lineage precursors. Identification of cytogenetic aberrations is essential for classification and risk stratification of AML, with many demonstrating unique associations with various clinicopathologic features. One such abnormality is MYC amplification, a rare occurrence identified in less than 1% of AML patients. MYC is most commonly amplified in the form of double minutes, but may also occur via ring and marker chromosomes or homogeneously staining regions. Amplification of MYC often involves various chromosomal aberrations, including trisomies 4 and 6 and aneusomy of the sex chromosomes. In many cases, the presence of MYC amplicons is also associated with other negative prognostic factors, including complex karyotype and advanced age. Although MYC has been extensively investigated as a therapeutic target in various cancers, there are few studies examining the clinical significance of MYC amplification in AML. In this review, we explore recurrent cytogenetic abnormalities and demographic characteristics associated with amplification of MYC in patients with AML and discuss their diagnostic and therapeutic implications.

Objectives: Acute myeloid leukemia (AML) is a group of diseases resulting from a clonal expansion of myeloid precursor cells in the bone marrow. Each subtype harbors characteristic clinical, morphologic, and molecular features. AML is most often de novo and arises from somatic mutations causing unchecked proliferation of myeloblasts, but it may also present as a secondary malignancy, often as the result of prior cytotoxic exposure. Here we present a case of therapy-related AML (t-AML) following chemotherapy exposure found to have a characteristic balanced translocation involving 11q23 and outline a potential mechanism of oncogenesis.

Objectives: The FMS-like tyrosine kinase 3 gene (FLT3) is a receptor tyrosine kinase expressed in early hematopoietic progenitors that play an important role in hematopoietic development. The signaling pathways that are stimulated by the FLT3 protein manage several crucial cellular processes including division, growth, and survival of cells, specifically of hematopoietic progenitor cells. Activating mutations of this gene have been highly discussed in myeloid malignancies, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). However, FLT3 mutations are also observed in around 5% of acute lymphoblastic leukemia (ALL) patients. These mutations were usually found to be one of the four types: internal tandem duplications, tyrosine kinase domain mutations, juxtamembrane insertion and deletion, and juxtamembrane point mutation. The presence of FLT3 mutations in pediatric B-ALL patient populations tend to be associated with relapse and poor prognosis. These mutations are also correlated with poor prognosis in adult B-ALL patients. Due to the rarity of FLT3 mutations in B-ALL patients, there have been many challenges in attempts to understand their role in pathogenesis. In this review, we will discuss the most recent literature and trends associated with FLT3 mutations in B-ALL patients in order to elucidate their cytogenetic, molecular, and clinical implications.

Objectives: A 67-year-old male patient was diagnosed with acute myeloid leukemia (AML) in April 2018. Chromosome analysis showed an abnormal male karyotype with an isodicentric chromosome 7q resulting in deletion 7q and two copies of 7p and a derivative chromosome 18 in 13 of the 20 metaphase cells examined. This karyotype was described as 46,XY,idic(7)(q11.2),der(18)t(1;18)(q23;q21.1)[13]/46,XY[7]. Additionally, subsequent sequencing analysis displayed FLT3-ITD and RUNX1 mutations (data not shown). The bone marrow showed an overwhelming number of blast cells, with co-expression of CD34, CD117, TdT, MPO, CD7, CD13, CD33, CD38, CD19, and HLA-DR. Molecular cytogenetic studies showed a deletion of one RELN/TES (7q22/7q31) signal in 80.5% of nuclei and a gain of a BCR/ABL1 (22q11.2/9q34) signal in 3.5% of interphase nuclei examined. These findings were described as nuc ish(RELN,TES)x1[161/200],(ABL1x2,BCRx3)[7/200], (EVI1,TAS2R1,EGR1,DEK,MYC,NUP214,KMT2A,DLEU1,DLEU2,Clone 163C9,PML,CBFB,RARA,PTPRT,MYBL2,RUNX1)x2[200]. The patient relapsed with AML in September 2019 and underwent treatment. However, all AML treatment options were exhausted by March 2020. An isodicentric chromosome 7 leading to two copies of the short arm of chromosome 7 (7p) and deletion 7q is a rare event in AML and is rarely described in the literature. The key element here is that this specific rearrangement leads to deletion 7q which is a well-known abnormality in AML that places the patient in the Poor/Adverse risk category.

Objectives: Ring chromosomes, which are formed through the fusion of the telomeric ends of a chromosome, present with a spectrum of symptoms whose severity depends on the amount of genetic material lost. Ring chromosome 13 cases present with symptoms similar to that of deletion 13q syndrome, and can be classified depending on whether several critical regions are involved in the deletion. An important region to consider is locus 13q32, whose deletion is known to cause severe phenotypes and major malformations. In contrast, deletions of the more distal locus 13q34 have been shown to be involved in symptoms such as microcephaly and ambiguous genitalia. Herein, we report a case of a pediatric patient with r(13) who presented with microcephaly, facial dysmorphism, hand and feet anomalies, and ambiguous genitalia. The karyotype was described as 46,XY,r(13)(p11.1q34). This case highlights the importance of cytogenetic analysis in determining the prognostic implications of ring chromosome cases.

Objectives: The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is an RNA-guided DNA targeting platform widely known for its application in genome editing. Originally derived from the bacterial and archaebacterial defense mechanism against phage infection, it has since been studied and utilized for its potential as a genetic engineering tool and as a therapeutic agent. The Cas9 protein in its standard form induces double-stranded breaks (DSBs) in the target dsDNA sequence; however, modifications of the Cas9 protein have allowed for single-stranded breaks (SSBs) and even epigenetic modifications of gene expression. In comparison with previous methods including RNA interference, Zinc Finger Nucleases, and TAL Effector Nucleases, CRISPR is cheaper, more easily customized, and has a higher fidelity to its target site with fewer off-target effects. Consequently, CRISPR has become a central gene editing technique in a broad variety of research settings, with great potential for applications in human health. In this review, we offer an overview of CRISPR's mechanism of action and recent advancements in the application of CRISPR, as well as discuss literature pertinent to CRISPR applications to human health including many exciting prospective treatments for serious pathologies.

Objectives: The ASXL1 (additional sex combs like 1) gene on 20q11 codifies the ASXL1 protein that belongs to protein complexes that play a role in gene expression and epigenetic regulation. ASXL1 is located near the DNMT3B gene and is part of a family of three genes (ASXL1, ASXL2, ASXL3) that are homologues to the Drosophila Asx gene. The ASXL1 gene contains a total of 14 exons and is expressed in the vast majority of hematopoietic cell types. While the specific job of ASXL1 in normal hematopoiesis and the involvement of mutated ASXL1 to the progression of hematopoietic malignancies have not yet been fully set forth, current data studies propose that ASXL1 is characterized as a tumor suppressor gene. Mutations in the ASXL1 gene are observed in myeloid malignancies usually associated with aggressiveness and poor clinical results and were reported first in the year 2009 in myelodysplastic syndromes (MDS). Nevertheless, ASXL1 gene mutations are also found in acute myeloid leukemia (AML) with normal karyotype as well as AML with myelodysplasia-related changes and AML with non-characteristic cytogenetic findings. Herein we examine the involvement of the ASXL1 gene in AML to address the importance of these ASXL1 mutations in the prognostic evaluation of AML.

Objectives: A 19-year-old male with a history of irritable bowel syndrome presented with progressive fatigue, periorbital petechiae, and abdominal pain for 2-3 weeks. The peripheral blood smear showed leukocytosis and circulating blasts. Elevated PT, PTT, and FDP with normal fibrinogen were found in the DIC panel workup. Abdominal CT suggested splenomegaly. A bone marrow biopsy revealed sheets of monotonous agranular monoblasts nearly completely replaced the hematopoietic elements. Chromosome analysis depicted an abnormal male karyotype with a t(9;11)(p22;q23) in all metaphase cells examined. Four cells showed, in addition, two 8q isochromosomes. FISH analysis was utilized with the MYC (8q24.21) probe from Abbott and the KMT2A (11q23), those of which showed gain on MYC and evidence of KMT2A. These findings correlate with the concurrent conventional cytogenetic findings and were described as nuc ish(MYCx4~9)[182/200],(KMT2Ax2)(5'KMT2A sep 3'KMT2Ax1)[181/200]. Complex karyotypes are associated with poor prognosis. Although only a few pediatric cases exist in the literature, the presence of additional abnormalities put this finding as a poor prognostic marker in AML. Correlation with other clinical data was indicated.