RAD21 mutations in acute myeloid leukemia.

The cohesin complex is a ring-shaped protein structure involved in DNA repair and chromosomal segregation. Studies have showed that genomic alterations in the cohesin complex members are among the initial occurrences in the development of acute myeloid leukemia (AML). STAG2 is the most commonly mutated and best-studied member of the cohesin complex in AML and mutations in this gene have been associated with adverse outcomes and are diagnostically relevant. However, the exact role of mutations in other members of the cohesin complex in the development of myeloid neoplasia is controversial. In this single institution study, we retrospectively reviewed data from the molecular profiles of 1,381 AML patients and identified 14 patients with mutations in RAD21, another member of the cohesin complex. We evaluated the frequency, mutational profile, clinico-pathologic features, and prognostic impact of RAD21 in this cohort. This study showed that RAD21-mutated AML often associates with monocytic differentiation, CD7 expression, co-existing mutations in epigenetic regulators, a normal karyotype, and poor prognosis. Our findings provide additional insights into the morphologic, immunophenotypic, and genomic profile of RAD21 mutation-positive AML and suggest that RAD21 mutations should be evaluated for independent prognostic significance in AML.

Cytogenetics and genomics of acute myeloid leukemia.

The diversity of genetic and genomic abnormalities observed in acute myeloid leukemia (AML) reflects the complexity of these hematologic neoplasms. The detection of cytogenetic and molecular alterations is fundamental to diagnosis, risk stratification and treatment of AML. Chromosome rearrangements are well established in the diagnostic classification of AML, as are some gene mutations, in several international classification systems. Additionally, the detection of new mutational profiles at relapse and identification of mutations in the pre- and post-transplant settings are illuminating in understanding disease evolution and are relevant to the risk assessment of AML patients. In this review, we discuss recurrent cytogenetic abnormalities, as well as the detection of recurrent mutations, within the context of a normal karyotype, and in the setting of chromosome abnormalities. Two new classification schemes from the WHO and ICC are described, comparing these classifications in terms of diagnostic criteria and entity definition in AML. Finally, we discuss ways in which genomic sequencing can condense the detection of gene mutations and chromosome abnormalities into a single assay.

Understanding patient preferences for student clinician attire: a cross-sectional study of a student chiropractic clinic in Australia.

Objectives: Previous studies have investigated the role of clinical attire in establishing patient-held perceptions of professionalism and knowledgeability across various healthcare settings. This study aimed to understand patients' preferences for chiropractic student attire. Methods: Three hundred and twenty patients were recruited from a university chiropractic clinic and asked to complete an online questionnaire. The patients' preferences for five different attires were rated and calculated as the composite score of five domains (knowledgeable, trustworthy, caring, professional, and comfortable). Results: While 71.9% of participants indicated that how students dress was important to them, most (63.4%) disagreed that wearing a white coat was essential for chiropractic student clinicians. The most preferred form of attire was the current clinic shirt. Conclusion: The attire worn by chiropractic student clinicians at a single institution was found to be an influential attribute. Student chiropractic clinicians should dress professionally to make a good first impression. This study provided some guidance with the ongoing debate around students' dress code.

Objectif: Des études antérieures ont examiné le rôle de la tenue vestimentaire en clinique dans l'établissement des perceptions des patients quant au professionnalisme et à la compétence dans divers environnements de soins de santé. Cette étude visait à comprendre les préférences des patients en matière de tenue vestimentaire des étudiants en chiropratique. Méthodologie: Trois cent vingt patients ont été recrutés dans une clinique chiropratique universitaire et invités à remplir un questionnaire en ligne. Les préférences des patients pour cinq tenues différentes ont été évaluées et calculées en tant que score composite de cinq domaines (bien informé, digne de confiance, attentionné, professionnel et confortable). Résultats: Si 71,9 % des participants ont indiqué que la tenue vestimentaire des étudiants était importante pour eux, la plupart (63,4 %) n'étaient pas d'accord avec le fait que le port d'une blouse blanche était essentiel pour les étudiants cliniciens en chiropratique. La tenue vestimentaire la plus appréciée était la chemise de clinique actuelle. Conclusion: La tenue vestimentaire des étudiants cliniciens en chiropratique d'un même établissement s'est révélée être un attribut influent. Les étudiants en chiropratique doivent s'habiller de manière professionnelle pour faire une bonne première impression. Cette étude a permis d'éclairer le débat en cours sur le code vestimentaire des étudiants.

Greater expectations: meeting clinical needs through broad and rapid genomic testing.

Cancer describes a group of diseases driven by genetic and genomic changes that can occur across hundreds of different genes. Knowledge of the specific variants present in a patient's cancer can help to predict response to different treatment options, confirm disease diagnosis, and understand a patient's prognosis and risks, which ultimately leads to improved survival outcomes. The advent of next-generation sequencing (NGS) technology has allowed pathologists to simultaneously profile the sequences of many genes in a single reaction, but not all NGS assays are built the same. While those used for broad genomic profiling are useful to probe large regions of the genome and gather more information about a patient's tumor, it comes at the cost of relatively long turnaround times (TAT), which may be detrimental to patient care. Conversely, NGS assays used for rapid genomic profiling provide faster results, but may miss detection of variants that are clinically informative. Determining which type of genomic profiling to order depends on a number of factors including the severity of a patient's illness, standard of care paradigms, and success or failure of previous therapies. Ultimately, the ideal clinical diagnostic laboratory will be able to offer both options to best meet the clinical needs of its patients.

NTRK point mutations and their functional consequences.

The neurotrophic receptor tyrosine kinase (NTRK) family of genes, including NTRK1, NTRK2, and NTRK3, encodes membrane-bound receptors that normally regulate cell survival and differentiation upon binding of growth factors. Not surprisingly, mutations in these genes are known to contribute to the growth of a diverse number of cancers. With the recent FDA approval of two first-generation tyrosine-kinase inhibitors (TKIs) for adult and pediatric patients with solid tumors harboring NTRK gene fusions, much of the literature has focused on the biology behind these types of NTRK abnormalities; however, point mutations can also contribute to oncogenesis or resistance to TKI therapy, albeit at a lower frequency than fusions. This review focuses on NTRK gene mutations that are associated with resistance to directed therapies, mutations detected in the primary setting that confer increased oncogenic activity, and evidence that suggests that some of these variants may be treated using specific targeted therapies. Finally, this review focuses on the detection of point mutations, including the utility of cell-free DNA (cfDNA) for monitoring the acquisition of resistance mutations.

A review of inherited cancer susceptibility syndromes.

Inherited cancer syndromes are caused by genetic mutations that place patients at an increased risk for developing cancer. Although most cancers are not caused by genetic inheritance, clinicians must understand these syndromes and be able to recognize their common characteristics. A thorough family history and identification of common patterns as well as specific clinical signs and symptoms can help with early recognition. This article describes symptoms of the more common cancer syndromes, including hereditary breast and ovarian cancer, Li-Fraumeni, Lynch, familial adenomatous polyposis, retinoblastoma, multiple endocrine neoplasia, and von Hippel-Lindau. Important patient education regarding genetic testing also is covered.

Mutant BRAF and MEK Inhibitors Regulate the Tumor Immune Microenvironment via Pyroptosis.

Combinations of BRAF inhibitors and MEK inhibitors (BRAFi + MEKi) are FDA-approved to treat BRAF V600E/K-mutant melanoma. Efficacy of BRAFi + MEKi associates with cancer cell death and alterations in the tumor immune microenvironment; however, the links are poorly understood. We show that BRAFi + MEKi caused durable melanoma regression in an immune-mediated manner. BRAFi + MEKi treatment promoted cleavage of gasdermin E (GSDME) and release of HMGB1, markers of pyroptotic cell death. GSDME-deficient melanoma showed defective HMGB1 release, reduced tumor-associated T cell and activated dendritic cell infiltrates in response to BRAFi + MEKi, and more frequent tumor regrowth after drug removal. Importantly, BRAFi + MEKi-resistant disease lacked pyroptosis markers and showed decreased intratumoral T-cell infiltration but was sensitive to pyroptosis-inducing chemotherapy. These data implicate BRAFi + MEKi-induced pyroptosis in antitumor immune responses and highlight new therapeutic strategies for resistant melanoma. SIGNIFICANCE: Targeted inhibitors and immune checkpoint agents have advanced the care of patients with melanoma; however, detailed knowledge of the intersection between these two research areas is lacking. We describe a molecular mechanism of targeted inhibitor regulation of an immune-stimulatory form of cell death and provide a proof-of-principle salvage therapy concept for inhibitor-resistant melanoma.See related commentary by Smalley, p. 176.This article is highlighted in the In This Issue feature, p. 161.

Gasdermins in Apoptosis: New players in an Old Game.

Apoptosis is a form of programmed cell death (PCD) that plays critical physiological roles in removing superfluous or dangerous cell populations that are unneeded or threatening to the health of the host organism. Although the molecular pathways leading to activation of the apoptotic program have been extensively studied and characterized starting in the 1970s, new evidence suggests that members of the gasdermin superfamily are novel pore-forming proteins that augment apoptosis by permeabilizing the mitochondria and participate in the final stages of the apoptotic program by inducing secondary necrosis/pyroptosis. These findings may explain outstanding questions in the field such as why certain gasdermin members sensitize cells to apoptosis, and why some apoptotic cells also show morphological features of necrosis. Furthermore, the interplay between the gasdermins and apoptosis may also explain why genetic and epigenetic alterations in these genes cause diseases and disorders like cancer and hearing loss. This review focuses on our current understanding of the function of several gasdermin superfamily members, their role in apoptosis, and how they may contribute to pathophysiological conditions.

Gasdermins: novel mitochondrial pore-forming proteins.

Gasdermin proteins have been extensively characterized for their ability to form necrotic pores in the plasma membrane, however, their interactions with other organelles have yet to be described. We recently demonstrated that some gasdermin proteins can also permeabilize the mitochondria to augment apoptotic signaling which may be important in the context of cancer and hearing loss.

Gasdermin pores permeabilize mitochondria to augment caspase-3 activation during apoptosis and inflammasome activation.

Gasdermin E (GSDME/DFNA5) cleavage by caspase-3 liberates the GSDME-N domain, which mediates pyroptosis by forming pores in the plasma membrane. Here we show that GSDME-N also permeabilizes the mitochondrial membrane, releasing cytochrome c and activating the apoptosome. Cytochrome c release and caspase-3 activation in response to intrinsic and extrinsic apoptotic stimuli are significantly reduced in GSDME-deficient cells comparing with wild type cells. GSDME deficiency also accelerates cell growth in culture and in a mouse model of melanoma. Phosphomimetic mutation of the highly conserved phosphorylatable Thr6 residue of GSDME, inhibits its pore-forming activity, thus uncovering a potential mechanism by which GSDME might be regulated. Like GSDME-N, inflammasome-generated gasdermin D-N (GSDMD-N), can also permeabilize the mitochondria linking inflammasome activation to downstream activation of the apoptosome. Collectively, our results point to a role of gasdermin proteins in targeting the mitochondria to promote cytochrome c release to augment the mitochondrial apoptotic pathway.

Cleavage of DFNA5 by caspase-3 during apoptosis mediates progression to secondary necrotic/pyroptotic cell death.

Apoptosis is a genetically regulated cell suicide programme mediated by activation of the effector caspases 3, 6 and 7. If apoptotic cells are not scavenged, they progress to a lytic and inflammatory phase called secondary necrosis. The mechanism by which this occurs is unknown. Here we show that caspase-3 cleaves the GSDMD-related protein DFNA5 after Asp270 to generate a necrotic DFNA5-N fragment that targets the plasma membrane to induce secondary necrosis/pyroptosis. Cells that express DFNA5 progress to secondary necrosis, when stimulated with apoptotic triggers such as etoposide or vesicular stomatitis virus infection, but disassemble into small apoptotic bodies when DFNA5 is deleted. Our findings identify DFNA5 as a central molecule that regulates apoptotic cell disassembly and progression to secondary necrosis, and provide a molecular mechanism for secondary necrosis. Because DFNA5-induced secondary necrosis and GSDMD-induced pyroptosis are dependent on caspase activation, we propose that they are forms of programmed necrosis.

Caspase-8 scaffolding function and MLKL regulate NLRP3 inflammasome activation downstream of TLR3.

TLR2 promotes NLRP3 inflammasome activation via an early MyD88-IRAK1-dependent pathway that provides a priming signal (signal 1) necessary for activation of the inflammasome by a second potassium-depleting signal (signal 2). Here we show that TLR3 binding to dsRNA promotes post-translational inflammasome activation through intermediate and late TRIF/RIPK1/FADD-dependent pathways. Both pathways require the scaffolding but not the catalytic function of caspase-8 or RIPK1. Only the late pathway requires kinase competent RIPK3 and MLKL function. Mechanistically, FADD/caspase-8 scaffolding function provides a post-translational signal 1 in the intermediate pathway, whereas in the late pathway it helps the oligomerization of RIPK3, which together with MLKL provides both signal 1 and 2 for inflammasome assembly. Cytoplasmic dsRNA activates NLRP3 independent of TRIF, RIPK1, RIPK3 or mitochondrial DRP1, but requires FADD/caspase-8 in wildtype macrophages to remove RIPK3 inhibition. Our study provides a comprehensive analysis of pathways that lead to NLRP3 inflammasome activation in response to dsRNA.