Fluorescent In Situ Hybridization for TP53 in the Diagnosis of Pediatric Osteogenic Sarcoma

The dCas9/crRNA linked immunological assay (dCLISA) for sensitive, accurate, and facile drug resistance gene analysis

The rapid and reliable diagnosis of methicillin-resistant Staphylococcus aureus (MRSA) is essential for preventing the spread of MRSA infections and guiding therapeutic strategies. However, there is still a huge challenge in further simplifying MRSA detection procedures and improving detection selectivity to reduce false-positive results. In this study, we developed a derivative CRISPR-associated protein 9/CRISPR-derived RNA Linked Immunological Assay (dCLISA) for the sensitive and specific detection of MRSA. This technique utilizes two dCas9/crRNA complexes as specific targeting agents and employs a color reaction mediated by a hybridization chain reaction for signal output. The dCLISA method offers certain benefits compared to monoclonal antibodies in traditional immunoassays, primarily due to its capacity to selectively interact with target gene and its high sensitivity from the hybridization chain reaction process. Therefore, the minimum detectable concentration of dCLISA was 8.5 cfu/mL. Unlike traditional gene analysis approaches, target gene sequences in cell lysates can be directly detected by dCLISA within 60 min with high sensitivity without genomic material extraction. In addition, the absorbance intensity of the MRSA cell lysate was significantly higher than that of methicillin-susceptible S. aureus (MSSA) indicates the clinical application potential. This study demonstrates that the dCLISA is a simple, rapid, sensitive, and specific method, which can be directly used at the point of care to analyze drug resistance in bacteria, including MRSA. Moreover, dCLISA can be utilized for other bacteria detection by merely modifying the crRNA sequence.

Bone Matrix-forming Tumors

Bone matrix-forming tumors are a group of neoplasms that exhibit differentiation toward any stage of osteoblast development. Their clinicopathologic features can resemble one another, yet their clinical management may vary significantly. Therefore, appropriate treatment requires accurate diagnosis, which can be challenging, especially with limited biopsy specimens. Recently, the driver genetic alterations underlying these neoplasms have been discovered, and their protein products can be targeted for diagnosis and therapy. Herein, we summarize the recent advances in our understanding of bone matrix-forming tumors and emphasize the integration of molecular genetics into their conventional clinicopathologic evaluation.

Japanese orthopaedic association (JOA) clinical practice guideline on the management of primary malignant bone tumors - Secondary publication

BACKGROUND

In Japan, there are currently no general guidelines for the treatment of primary malignant bone tumors. Therefore, the Japanese Orthopaedic Association established a committee to develop guidelines for the appropriate diagnosis and treatment of primary malignant bone tumors for medical professionals in clinical practice.

METHODS

The guidelines were developed in accordance with "Minds Clinical Practice Guideline Development Handbook 2014″ and "Minds Clinical Practice Guideline Development Manual 2017". The Japanese Orthopaedic Association's Bone and Soft Tissue Tumor Committee established guideline development and systematic review committees, drawing members from orthopedic specialists leading the diagnosis and treatment of bone and soft tissue tumors. Pediatricians, radiologists, and diagnostic pathologists were added to both committees because of the importance of multidisciplinary treatment. Based on the diagnosis and treatment algorithm for primary malignant bone tumors, important decision-making points were selected, and clinical questions (CQ) were determined. The strength of recommendation was rated on two levels and the strength of evidence was rated on four levels. The recommendations published were selected based on agreement by 70% or more of the voters.

RESULTS

The guideline development committee examined the important clinical issues in the clinical algorithm and selected 22 CQs. The systematic review committee reviewed the evidence concerning each CQ and a clinical value judgment was added by experts. Eventually, 25 questions were published and the text of each recommendation was determined.

CONCLUSION

Since primary malignant bone tumors are rare, there is a dearth of strong evidence based on randomized controlled trials, and recommendations cannot be applied to all the patients. In clinical practice, appropriate treatment of patients with primary malignant bone tumors should be based on the histopathological diagnosis and degree of progression of each case, using these guidelines as a reference.

Genomic Landscape of Osteosarcoma of Bone in an Older-Aged Patient Population and Analysis of Possible Etiologies Based on Molecular Signature

Background: Osteosarcoma (OS), the most common primary malignant bone tumor, occurs mostly in the pediatric and adolescent (P/A) population where it has been subject to intense study whereas OS arising in the older-aged adult population has undergone less scrutiny. Materials and Methods: In this study, we assess the molecular aberrations detected in eight older adult patients (>59 years of age) with OS of bone by whole-exome sequencing (WES) on formalin-fixed, paraffin-embedded tissue and quantified the contributions of endogenous and exogenous mutational processes to tumor mutational burden and to tumorigenesis through computational analysis. Results: We identified 86 clinically significant somatic mutations. TP53 mutations occurred in OSs of three patients and one patient harbored a pathogenic germline mutation of TP53. Loss-of-heterozygosity of DNA-damage repair genes occurred in all six tumors evaluated. Computational analysis of single nucleotide variants within each tumor detected eight distinct mutagenic processes of which age-associated mutational processes, thiopurine chemotherapy, and defective homologous DNA recombination repair contributed the most to both tumor mutation burden and tumor pathogenesis. Conclusion: The genomic landscape of our older OS patients deciphered by WES is extremely diverse with only 15% of mutated somatic genes uncovered in our study previously described in P/A-enriched OS studies. Endogenous age-related mutagenic processes, defective DNA homologous recombination repair, and exogenous effects of chemotherapy are mainly responsible for pathogenic mutations in OS occurring in our cohort.

3D-Printed Magnesium Peroxide-Incorporated Scaffolds with Sustained Oxygen Release and Enhanced Photothermal Performance for Osteosarcoma Multimodal Treatments

The hypoxic microenvironment in osteosarcoma inevitably compromises the antitumor effect and local bone defect repair, suggesting an urgent need for sustained oxygenation in the tumor. The currently reported oxygen-releasing materials have short oxygen-releasing cycles, harmful products, and limited antitumor effects simply by improving hypoxia. Therefore, the PCL/nHA/MgO2/PDA-integrated oxygen-releasing scaffold with a good photothermal therapy effect was innovatively constructed in this work to achieve tumor cell killing and bone regeneration functions simultaneously. The material distributes MgO2 powder evenly on the scaffold material through 3D printing technology and achieves the effect of continuous oxygen release (more than 3 weeks) through its slow reaction with water. The in vitro and in vivo results also indicate that the scaffold has good biocompatibility and sustained-release oxygen properties, which can effectively induce the proliferation and osteogenic differentiation of bone mesenchymal stem cells, achieving excellent bone defect repair. At the same time, in vitro cell experiments and subcutaneous tumorigenesis experiments also confirmed that local oxygen supply can promote osteosarcoma cell apoptosis, inhibit proliferation, and reduce the expression of heat shock protein 60, thereby enhancing the photothermal therapy effect of polydopamine and efficiently eliminating osteosarcoma. Taken together, this integrated functional scaffold provides a unique and efficient approach for antitumor and tumor-based bone defect repair for osteosarcoma treatment.