Acute promyelocytic leukemia with isochromosome 17q and cryptic PML-RARA successfully treated with all-trans retinoic acid and arsenic trioxide

Utilization of RT-PCR and Optical Genome Mapping in Acute Promyelocytic Leukemia with Cryptic PML::RARA Rearrangement: A Case Discussion and Systemic Literature Review

BACKGROUND

Acute promyelocytic leukemia (APL) is characterized by abnormal promyelocytes and t(15;17)(q24;q21) PML::RARA. Rarely, patients may have cryptic or variant rearrangements. All-trans retinoic acid (ATRA)/arsenic trioxide (ATO) is largely curative provided that the diagnosis is established early.

METHODS

We present the case of a 36-year-old male who presented with features concerning for disseminated intravascular coagulation. Although the initial diagnostic work-up, including pathology and flow cytometry evaluation, suggested a diagnosis of APL, karyotype and fluorescence in situ hybridization (FISH), using the PML/RARA dual fusion and RARA breakapart probes, were negative. We performed real-time polymerase chain reaction (RT-PCR) and optical genome mapping (OGM) to further confirm the clinicopathological findings.

RESULTS

RT-PCR revealed a cryptic PML::RARA fusion transcript. OGM further confirmed the nature and orientation of a cryptic rearrangement with an insertion of RARA into PML at intron 3 (bcr3). In light of these findings, we performed a systematic literature review to understand the prevalence, diagnosis, and prognosis of APL with cryptic PML::RARA rearrangements.

CONCLUSIONS

This case, in conjunction with the results of our systematic literature review, highlights the importance of performing confirmatory testing in FISH-negative cases of suspected APL to enable prompt diagnosis and appropriate treatment.

Biologic and Clinical Characteristics of Isochromosome der(17)(q10)t(15;17) in Acute Promyelocytic Leukemia

INTRODUCTION

Acute promyelocytic leukemia (APL) is genetically characterized by the fusion of promyelocytic leukemia (PML) gene with retinoic acid receptor alpha (RARα) resulting from a t(15;17)(q24;q21) chromosomal translocation. An infrequent but recurrent finding in APL is the formation of an isochromosome of the derivative chromosome 17; ider(17)(q10)t(15;17) or ider(17q). This rearrangement in APL results in an additional copy of the PML-RARα fusion gene as well as loss of 17p/TP53. Due to the infrequent occurrence of the ider(17q), the prognostic impact of this genetic finding is not well known. Case Presentation(s): Here, we describe the clinical characteristics and outcomes of our case series of 5 patients with ider(17q) APL treated at the University of Maryland and Johns Hopkins University.

CONCLUSION

In our series, patients with APL with ider(17q) did not have a worse prognosis.

An overview of arsenic trioxide-involved combined treatment algorithms for leukemia: basic concepts and clinical implications

Arsenic trioxide is a first-line treatment drug for acute promyelocytic leukemia, which is also effective for other kinds of leukemia. Its side effects, however, limit its clinical application, especially for patients with complex leukemia symptoms. Combination therapy can effectively alleviate these problems. This review summarizes the research progress on the combination of arsenic trioxide with anticancer drugs, vitamin and vitamin analogs, plant products, and other kinds of drugs in the treatment of leukemia. Additionally, the new progress in arsenic trioxide-induced cardiotoxicity was summarized. This review aims to provide new insights for the rational clinical application of arsenic trioxide.

[Cytogenetic test and clinical study on cryptic acute promyelocytic leukemia with ins (15; 17)]

Objective: To investigate the genetic screening methods for cryptic acute promyelocytic leukemia (APL) to further explore its clinical prognosis. Methods: From June 2016 to November 2018, we collected 373 newly diagnosed APL cases. The patients were retrospected by the results of PML-RARα detections both by RT-PCR and i-FISH, those who harbored positive PML-RARα detection by RT-PCR and negative by i-FISH were chosen. Metaphase FISH and Sanger sequencing were further performed to verify these results. Results: A total of 7 cryptic APL cases were discovered. These cases had tiny fragment of RARα inserted into PML in chromosome 15, formed ins (15;17) . The 7 cryptic APL cases had no PML-RARα gene subtype specificity, involving 5 cases in L subtype, 1 case in S subtype and 1 case in V subtype respectively. After the treatment of retinoic acid and arsenic or anthracyclines, 6 cases achieved complete remission, 1 case died of intracranial hemorrhage on the 6th day of therapy. Conclusion: The size and covering position of PML-RARα probe should be taken into account when PML-RARα was performed by FISH on APL patients. Furthermore, combination with Metaphase FISH could improve the recognition of cryptic APL. There were no differences between the cryptic and common APL patients in terms of clinical features and treatment choices. Cryptic APL patients also had a good response to the therapy of retinoic acid and arsenic or anthracyclines.

Chlorogenic acid effectively treats cancers through induction of cancer cell differentiation

Rationale: Inducing cancer differentiation is a promising approach to treat cancer. Here, we identified chlorogenic acid (CA), a potential differentiation inducer, for cancer therapy, and elucidated the molecular mechanisms underlying its differentiation-inducing effects on cancer cells.

Methods: Cancer cell differentiation was investigated by measuring malignant behavior, including growth rate, invasion/migration, morphological change, maturation, and ATP production. Gene expression was analyzed by microarray analysis, qRT-PCR, and protein measurement, and molecular biology techniques were employed for mechanistic studies. LC/MS analysis was the method of choice for chemical detection. Finally, the anticancer effect of CA was evaluated both in vitro and in vivo.

Results: Cancer cells treated with CA showed reduced proliferation rate, migration/invasion ability, and mitochondrial ATP production. Treating cancer cells with CA resulted in elevated SUMO1 expression through acting on its 3'UTR and stabilizing the mRNA. The increased SUMO1 caused c-Myc sumoylation, miR-17 family downregulation, and p21 upregulation leading to G₀/G₁ arrest and maturation phenotype. CA altered the expression of differentiation-related genes in cancer cells but not in normal cells. It inhibited hepatoma and lung cancer growth in tumor-bearing mice and prevented new tumor development in naïve mice. In glioma cells, CA increased expression of specific differentiation biomarkers Tuj1 and GFAP inducing differentiation and reducing sphere formation. The therapeutic efficacy of CA in glioma cells was comparable to that of temozolomide. CA was detectable both in the blood and brain when administered intraperitoneally in animals. Most importantly, CA was safe even at very high doses.

Conclusion: CA might be a safe and effective differentiation-inducer for cancer therapy. “Educating” cancer cells to differentiate, rather than killing them, could be a novel therapeutic strategy for cancer.

An Atypical PML-RARA Rearrangement Resulting from Submicroscopic Insertion of the RARA Gene at the PML Locus with Novel Breakpoints within PML Exon 7b and RARA Exon 3

The diagnostic hallmark of acute promyelocytic leukemia (APL) is the reciprocal translocation t(15;17), resulting in the characteristic PML-RARA fusion; however, patients occasionally have masked PML-RARArearrangements. We report an APL case with no evidence of t(15;17) or PML-RARA rearrangement by karyotype or commercial reverse transcription polymerase chain reaction analyses. Fluorescence in situ hybridization detected a small RARA insertion signal within PML. mRNA sequencing identified a novel PML-RARA transcript generated from the juxtaposition of PMLIIa (exons 1-4, 6, and 7ab) and RARA exons (3-9), with novel breakpoints in PML exon 7b and RARA exon 3. The patient achieved molecular remission after the second consolidation chemotherapy and remains in complete remission 22 months after initial presentation. This is the first report of an APL case presenting with submicroscopic ins(15;17) and simultaneous novel breakpoints in both PML and RARA. This case highlights the importance of sequence analysis to confirm APL diagnosis and for subsequent monitoring of minimal residual disease.

Isoderivative chromosome 17 with multiple copies of RARα-PML fusions and Tp53 deletion in a rare case of APML

Acute Promyelocytic Leukemia (APML) is a malignancy of cells in myeloid lineage. It is a neoplasm described by proliferation and accumulation of immature neutrophils called promyelocytes in the bone marrow, inhibiting normal cell production, which results in lower numbers of blood cells circulating the body. A minor but significant proportion of patients with APML harbor complex and cryptic rearrangements. Presence of isoderivative 17 with t(15;17) is very rare. We report a case of adult APML with amplification of RARα/PML fusion protein, a consequence of isoderivative 17 with duplication of normal chromosome 15 and 17 and Tp53 deletion on derivative 17. Immunophenotyping by flow cytometry, presence of pancytopenia and epistaxis helped classify the patient as APML. FISH was used for confirmation of the same and indicated involvement of additional abnormalities.

Personalized medicine in non-small cell lung cancer: a review from a pharmacogenomics perspective

Non-small cell lung cancer is a prevalent and rapidly-expanding challenge to modern medicine. While generalized medicine with traditional chemotherapy yielded comparatively poor response rates and treatment results, the cornerstone of personalized medicine using genetic profiling to direct treatment has exalted the successes seen in the field and raised the standard for patient treatment in lung and other cancers. Here, we discuss the current state and advances in the field of personalized medicine for lung cancer, reviewing several of the mutation-targeting strategies that are approved for clinical use and how they are guided by patient genetic information. These classes include inhibitors of tyrosine kinase (TKI), anaplastic lymphoma kinase (ALK), and monoclonal antibodies. Selecting from these treatment plans and determining the optimal dosage requires in-depth genetic guidance with consideration towards not only the underlying target genes but also other factors such as individual metabolic capability and presence of resistance-conferring mutations both directly on the target gene and along its cascade(s). Finally, we provide our viewpoints on the future of personalized medicine in lung cancer, including target-based drug combination, mutation-guided drug design and the necessity for data of population genetics, to provide rough guidance on treating patients who are unable to get genetic testing.

Environmental arsenic exposure: From genetic susceptibility to pathogenesis

More than 200 million people in 70 countries are exposed to arsenic through drinking water. Chronic exposure to this metalloid has been associated with the onset of many diseases, including cancer. Epidemiological evidence supports its carcinogenic potential, however, detailed molecular mechanisms remain to be elucidated. Despite the global magnitude of this problem, not all individuals face the same risk. Susceptibility to the toxic effects of arsenic is influenced by alterations in genes involved in arsenic metabolism, as well as biological factors, such as age, gender and nutrition. Moreover, chronic arsenic exposure results in several genotoxic and epigenetic alterations tightly associated with the arsenic biotransformation process, resulting in an increased cancer risk. In this review, we: 1) review the roles of inter-individual DNA-level variations influencing the susceptibility to arsenic-induced carcinogenesis; 2) discuss the contribution of arsenic biotransformation to cancer initiation; 3) provide insights into emerging research areas and the challenges in the field; and 4) compile a resource of publicly available arsenic-related DNA-level variations, transcriptome and methylation data. Understanding the molecular mechanisms of arsenic exposure and its subsequent health effects will support efforts to reduce the worldwide health burden and encourage the development of strategies for managing arsenic-related diseases in the era of personalized medicine.

Wip1 regulates SKOV3 cell apoptosis through the p38 MAPK signaling pathway

The aim of the present study was to explore the effect of silencing wild-type p53-induced phosphatase 1 (Wip1) on apoptosis of human ovarian cancer SKOV3 cells. SKOV3 cells cultured in vitro were divided into three groups: untreated cells, cells transfected with control small interfering RNA (siRNA) and cells transfected with siRNA targeting Wip1. Flow cytometry analysis was used to detect cell apoptosis. Western blot analysis was performed to determine expression of tumor protein 53 (p53), cleaved caspase-3, caspase-3, BCL2 associated X (Bax), BCL2 apoptosis regulator (Bcl-2), p38 mitogen-activated protein kinase (p38 MAPK) and phosphorylated (p)-p38 MAPK. Reverse transcription-quantitative polymerase chain reaction was used to detect expression of p53, Bax, Bcl-2 and caspase-3 mRNAs. Compared with control, apoptosis of SKOV3 cell was significantly increased following Wip1 siRNA silencing. Wip1 silencing also resulted in a significant increase of p53 and p-p38 MAPK expression, as well as increased cleaved caspase-3/caspase-3 and Bax/Bcl-2 protein ratios. No significant differences were observed in apoptosis and apoptosis-related protein expression in the control siRNA transfected cells. The present study demonstrated that Wip1 silencing promotes apoptosis of human ovarian cancer SKOV3 cells by activation of the p38 MAPK signaling pathways and through subsequent upregulation of p53, and cleaved caspase-3/caspase-3 and Bax/Bcl-2 protein ratios. Overall, the findings of the present study suggest that targeting Wip1 may be a potential therapeutic avenue for the treatment of human ovarian cancer in the future.

Acute promyelocytic leukemia with a cryptic insertion of RARA into PML on chromosome 15 due to uniparental isodisomy: A case report

Acute promyelocytic leukemia is a myeloid disorder that is characterized by the specific t(15;17) variant in ~98% of cases. The typical hypergranular and microgranular or hypogranular types exist, and are frequently associated with disseminated intravascular coagulopathy. Rare cases of promyelocytic leukemia-retinoic acid receptor α (PML-RARA) fusion without the reciprocal RARA-PML have been reported in cytogenetically normal samples. Conversely, fluorescence in situ hybridization (FISH) analysis has revealed a cryptic insertion of the RARA gene into the PML gene on chromosome 15. The current study reports a unique case with a normal karyotype and molecular evidence of the PML-RARA short isoform 3-fusion transcript, with FISH analysis revealing two fusion signals on the two copies of chromosome 15, but absence of the reciprocal on the two copies of chromosome 17. This finding raised the hypothesis of chromosome 15 uniparental isodysomy as consequence of normal chromosome 15 loss and duplication of the rearranged chromosome, as supported by polymorphic loci molecular analysis. The clinical, cytogenetic and molecular characterization of this case are presented and discussed in the present study.