Cytogenetic and molecular analysis of an unusual case of acute promyelocytic leukemia with a t(15;17;17)(q22;q23;q21)

Harnessing intermolecular G-quadruplex-based spatial confinement effect for accelerated activation of CRISPR/Cas12a empowers ultra-sensitive detection of PML/RARA fusion genes

Accurate detection and classification of the three isoforms of PML/RARA genomic fragments are crucial for predicting disease progression, stratifying risk, and administering precise drug therapies in acute promyelocytic leukemia (APL). In this study, we have developed a highly specific nucleic acid detection platform capable of quantifying the long isoform of the three main PML-RARA isoforms at a constant temperature. This platform integrates the strengths of the CRISPR/Cas12a nuclease-based method and the rolling circle amplification (RCA) technique. Notably, the RCA-assisted CRISPR/Cas12a trans-cleavage system incorporates a spatial confinement effect by utilizing intermolecular G-quadruplex structures. This innovative design effectively enhances the local concentration of CRISPR/Cas12a, thereby accelerating its cleaving efficiency towards reporter nucleic acids and enabling the detection of PML/RARA fusion gene expression through spectroscopy. The robust detection of PML/RARA fusion gene from human serum samples validates the reliability and potential of this platform in the screening, diagnosis, and prognosis of APL cases. Our findings present an approach that holds significant potential for the further development of the robust CRISPR/Cas sensor system, offering a rapid and adaptable paradigm for APL diagnosis.

A three‑way complex translocation of (15;15;17)(q24;q14;q21) involving two breakpoints on chromosome 15 in acute promyelocytic leukemia: A case report

The present study described an extremely rare case of acute promyelocytic leukemia (APL) characterized by a complex three-way (15;15;17)(q24;q14;q21) translocation. It was identified in a 59-year-old male through karyotype, molecular, and fluorescence in situ hybridization (FISH) analyses. The third translocation breakpoint 15q14 was identified on the same chromosome 15 that also contained the classical t(15;17)(q24;q21) and may have evolved from the classical t(15;17) clone, as indicated by interphase FISH analysis. A complex translocation involving two breakpoints on the same chromosome is extremely rare, such that this case can provide insights into complex translocations in APL.

Electrochemical Biosensors in the Diagnosis of Acute and Chronic Leukemias

Until now, morphological assessment with an optical or electronic microscope, fluorescence in situ hybridization, DNA sequencing, flow cytometry, polymerase chain reactions, and immunohistochemistry have been employed for leukemia identification. Nevertheless, despite their numerous different vantages, it is difficult to recognize leukemic cells correctly. Recently, the electrochemical evaluation with a nano-sensing interface seems an attractive alternative. Electrochemical biosensors measure the modification in the electrical characteristics of the nano-sensing interface, which is modified by the contact between a biological recognition element and the analyte objective. The implementation of nanosensors is founded not on single nanomaterials but rather on compilating these components efficiently. Biosensors able to identify the molecules of deoxyribonucleic acid are defined as DNA biosensors. Our review aimed to evaluate the literature on the possible use of electrochemical biosensors for identifying hematological neoplasms such as acute promyelocytic leukemia, acute lymphoblastic leukemia, and chronic myeloid leukemia. In particular, we focus our attention on using DNA electrochemical biosensors to evaluate leukemias.

2'-Fluoro ribonucleic acid modified DNA dual-probe sensing strategy for enzyme-amplified electrochemical detection of double-strand DNA of PML/RARα related fusion gene

In the study, a novel sensing strategy based on dual-probe mode, which involved two groups of 2'-fluoro ribonucleic acid (2'-F RNA) modified probes, was designed for the detection of synthetic target double-strand DNA (dsDNA) of PML/RARα fusion genes in APL. And each pair of probes contained a thiolated capture probe (C1 or C2) immobilized on one of electrode surfaces in the dual-channel electrochemical biosensor and a biotinylated reporter probe (R1 or R2). The two groups of 2'-F RNA modified probes were separately complementary with the corresponding strand (Sa or Sb) from target dsDNA in order to prevent renaturation of target dsDNA. Through flanking target dsDNA, two "sandwitch" complexes (C1/Sa/R1 and C2/Sb/R2) were separately shaped by capture probes (C1 and C2) and free reporter probes (R1 and R2) in hybridization solution on the surfaces of different electrodes after the thermal denaturation. The biotin-modified enzyme which produced the measurable electrochemical current signal was localized to the surface by affinity binding between biotin with streptavidin. Under the optimal condition, the biosensor was able to detect 84 fM target dsDNA and showed a good specificity in PBS hybridization solution. Otherwise, the investigations of the specificity and sensitivity of the biosensor were carried out further in the mixed hybridization solution containing different kinds of mismatch sequences as interference background. It can be seen that under a certain interference background, the method still exhibited excellent selectivity and specificity for the discrimination between the fully-complementary and the mismatch sequences. The results of our research laid a good basis of further detection research in practical samples.

A complex translocation (3;17;15) in acute promyelocytic leukemia confirmed by fluorescence in situ hybridization

Acute promyelocytic leukemia (APL) is typified by t(15;17)(q22;q21), generating the promyelocytic leukemia (PML) gene at 15q22 with the retinoic acid α-receptor (RARA) gene at 17q21. The PML-RARA fusion gene is believed to play a vital role in leukemogenesis. A sizeable minority of patients with complex variants of APL have been reported. The present study reports the case of a 33-year-old male with APL carrying a potential complex translocation. The initial symptom was bleeding gums. Chromosomal analysis of the bone marrow cells revealed an atypical 17q aberration. Fluorescence in situ hybridization further indicated that 92% of analyzed cells were positive for the PML-RARA fusion gene. The patient experienced complete remission following treatment with arsenic trioxide and chemotherapy. The atypical translocations in acute promyelocytic leukemia require further investigation.

New nanoplatforms based on upconversion nanoparticles and single-walled carbon nanohorns for sensitive detection of acute promyelocytic leukemia

New nanoplatforms were prepared by using upconversion nanoparticles as energy donor and single-walled carbon nanohorns as energy acceptor.

Coexistence of t(15;17) and t(15;16;17) detected by fluorescence in situ hybridization in a patient with acute promyelocytic leukemia: A case report and literature review

Acute promyelocytic leukemia (APL) is characterized by the t(15;17)(q22;q21), which results in the fusion of the promyelocytic leukemia (PML) gene at 15q22 with the retinoic acid α-receptor (RARA) gene at 17q21. The current study presents the case of a 54-year-old female with APL carrying the atypical PML/RARA fusion signal due to a novel complex variant translocation t(15;16;17)(q22;q24;q21), as well as the classical PML/RARA fusion signal. Subsequent array comparative genomic hybridization revealed somatic, cryptic deletions on 3p25.3, 8q23.1 and 12p13.2-p13.1, and a duplication on 8q11.2; however, no genetic material loss or gain was observed in the breakpoint regions of chromosomes 15, 16 or 17. To the best of our knowledge, this is the first report of the coexistence of two abnormal clones, one classical and one variant, presenting simultaneously in addition to cryptic chromosome segmental imbalances in an adult APL patient.

Design of a sandwich-mode amperometric biosensor for detection of PML/RARα fusion gene using locked nucleic acids on gold electrode

In this study, a novel DNA electrochemical probe (locked nucleic acid, LNA) was designed and involved in constructing an electrochemical DNA biosensor for detection of promyelocytic leukemia/retinoic acid receptor alpha (PML/RARα) fusion gene in acute promyelocytic leukemia for the first time. This biosensor was based on a 'sandwich' sensing mode, which involved a pair of LNA probes (capture probe immobilized at electrode surface and biotinyl reporter probe as an affinity tag for streptavidin-horseradish peroxidase (streptavidin-HRP). Since biotin can be connected with streptavidin-HRP, this biosensor offered an enzymatically amplified electrochemical current signal for the detection of target DNA. In the simple hybridization system, DNA fragment with its complementary DNA fragment was evidenced by amperometric detection, with a detection limit of 74 fM and a linear response range of 0.1-10 pM for synthetic PML/RARα fusion gene in acute promyelocytic leukemia (APL). Otherwise, the biosensor showed an excellent specificity to distinguish the complementary sequence and different mismatch sequences. The new pattern also exhibited high sensitivity and selectivity in mixed hybridization system.

A new three-way variant t(15;22;17)(q22;q11.2;q21) in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is characterized by the t(15;17)(q22;q21), which results in the fusion of the promyelocytic leukemia (PML) gene at 15q22 with the retinoic acid alpha-receptor (RARA) at 17q21. We report the case of a 44-year-old man with APL carrying a new complex variant translocation (15;22;17). Karyotypic analysis with G-banding of bone marrow cells revealed t(15;22;17) (q22;q11.2;q21). Fluorescence in situ hybridization with a PML/RARA dual-color DNA probe showed the fusion signals. RT-PCR analysis showed long-form PML/RARA fusion transcripts. A complete remission was attained with a course of conventional chemotherapy with all-trans retinoic acid (ATRA). This is the first report of a new three-way translocation of 22q11 involvement with APL.

A new complex translocation t(5;17;15)(q11;q21;q22) in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is associated with the t(15;17)(q22;q21) translocation which causes the fusion of the retinoic acid alpha gene (RARA) on 17q21 to the promyelocytic leukemia gene (PML) on 15q22. The two chimeric genes, PML/RARA and RARA/PML, are thought to play a role in leukemogenesis. A small proportion of patients with APL have complex or simple variants of this translocation. We report the case of a 22-year-old woman with APL carrying a complex variant translocation t(5;17;15)(q11;q12;q22) confirmed by G-banding, reverse transcription polymerase chain reaction (RT-PCR), fluorescence in situ hybridization(FISH), and spectral karyotyping analysis (SKY). The patient achieved complete remission with all-trans retinoic acid treatment and chemotherapy. These results illustrate the usefulness of combined analysis consisting of G-banding, RT-PCR, FISH, and SKY methods to identify the PML/RARA fusion gene in cases with variant t(15;17).

Variant acute promyelocytic leukemia translocation (15;17) originating from two subsequent balanced translocations involving the same chromosomes 15 and 17 while preserving the PML/RARA fusion

Fluorescence in situ hybridization (FISH) analysis of the bone marrow of a 24-year-old man diagnosed with acute promyelocytic leukemia (APL) revealed a variant pattern with one fusion signal instead of the typical two fusions expected with the probe set used. The combined FISH and conventional chromosome analyses suggested that two subsequent translocations had occurred in this patient involving the same chromosomes 15 and 17. As the prognostic outcome in APL is strictly associated with the presence of a PML/RARA fusion, it is useful and necessary to perform both cytogenetic and FISH analyses of a variant t(15;17) to determine the status of the PML/RARA fusion.

Acute promyelocytic leukemia with PML-RARA fusion on i(17q) and therapy-related acute myeloid leukemia

We describe a patient with acute promyelocytic leukemia (APL) and the karyotype 46,XX,i(17)(q10) with PML-RARA fusion gene detected by fluorescence in situ hybridization (FISH) and nested reverse transcriptase-polymerase chain reaction (RT-PCR). FISH using dual-color translocation probes for PML (promyelocytic leukemia) and RARA (retinoic acid receptor-alpha) showed fusion signal for PML-RARA on both arms of i(17q). The patient attained complete remission (CR) with all-trans retinoic acid treatment and became PML-RARA negative. One year later, while PML-RARA negative on FISH and RT-PCR, the patient presented with thrombocytopenia. Bone marrow examination suggested an acute monoblastic leukemia (AML-M5a) including the karyotype 46,XX,t(8;16) (p11.2;p13.3),inv(11)(p15q22 approximately q23)[11]/47,idem,+i(8)(q10)[9]. She is currently in CR. The occurrence of therapy related acute leukemia after successful therapy for APL is an emerging problem.

A new variant t(6;15;17)(q25;q22;q21) in acute promyelocytic leukemia: fluorescence in situ hybridization confirmation

Acute promyelocytic leukemia (APL) is characterized by the t(15;17)(q22;q21), which results in the fusion of the promyelocytic leukemia (PML) gene at 15q22 with the retinoic acid alpha-receptor (RARalpha) at 17q21. The 2 chimeric genes PML/RARalpha and RARalpha/PML are thought to play a role in leukemogenesis. We report a case of APL in a patient carrying an apparently complex variant translocation identified as t(6;15;17) by R-banding and whole chromosome 15 and 17 painting. However, FISH analysis with a PML/RARalpha dual-color kit showed a more complex translocation, resulting presumably from a two-step rearrangement, with PML-RARalpha fusion gene located as expected on the der(15) but the residual 5'-RARalpha signal located on the der(6). The patient achieved complete remission with all-trans retinoic acid treatment associated with chemotherapy. This case illustrates the usefulness of combined cytogenetics, FISH, and molecular biology to evidence the PML/RARalpha fusion gene in complex cases.