A rare case of primary central nervous system histiocytic sarcoma harboring a novel ARHGAP45::BRAF fusion: a case report and literature review.

INTRODUCTION: Patients with histiocytic sarcoma occurring in the central nervous system (CNS) are rare and have a very poor prognosis. The increased use of molecular diagnostic approaches in solid tumors has brought more opportunities for the diagnosis and treatment of central nervous system histiocytic sarcoma (CNSHS). CASE DESCRIPTION: A 9-year-old girl was admitted to the hospital with pain in her head and neck, as well as vomiting. Imaging scans showed a prominent abnormality in the anterior falciform region, and histopathology revealed the presence of CD68 (+) and CD163 (+) cells, leading to a preliminary diagnosis of primary intracerebral CNSHS. Molecular profiling tests identified a new variant of ARHGAP45::BRAF fusion in this case, which has not been reported in any other tumor. The patient underwent surgical removal of the tumor and will require long-term monitoring. CONCLUSION: The presence of the BRAF point mutation, predominantly BRAF p.V600E, has been documented in prior literature of CNSHS. This is the first case of pediatric histiocytic sarcoma in the anterior falciform region who has a unique ARHGAP45::BRAF fusion. The findings of our study indicate that a broader range of molecular assays should be employed in the diagnosis of CNSHS and opens up new possibilities for the treatment of the patient.

Comprehensive genomic analysis of primary bone sarcomas reveals different genetic patterns compared with soft tissue sarcomas.

Introduction: Sarcomas are classified into two types, bone sarcoma and soft tissue sarcoma (STS), which account for approximately 1% of adult solid malignancies and 20% of pediatric solid malignancies. There exist more than 50 subtypes within the two types of sarcoma. Each subtype is highly diverse and characterized by significant variations in morphology and phenotypes. Understanding tumor molecular genetics is helpful in improving the diagnostic accuracy of tumors that have been difficult to classify based on morphology alone or that have overlapping morphological features. The different molecular characteristics of bone sarcoma and STS in China remain poorly understood. Therefore, this study aimed to analyze genomic landscapes and actionable genomic alterations (GAs) as well as tumor mutational burden (TMB), microsatellite instability (MSI), and programmed death ligand-1 (PD-L1) expression among Chinese individuals diagnosed with primary bone sarcomas and STS. Methods: This retrospective study included 145 patients with primary bone sarcomas (n = 75) and STS (n = 70), who were categorized based on the 2020 World Health Organization classification system. Results: Patients diagnosed with bone sarcomas were significantly younger than those diagnosed with STS (p < 0.01). The top 10 frequently altered genes in bone sarcoma and STS were TP53, CDKN2A, CDKN2B, MAP3K1, LRP1B, MDM2, RB1, PTEN, MYC, and CDK4.The EWSR1 fusions exhibited statistically significant differences (p < 0.01) between primary bone sarcoma and STS in terms of their altered genes. Based on the actionable genes defined by OncoKB, actionable GAs was found in 30.7% (23/75) of the patients with bone sarcomas and 35.7% (25/70) of those with STS. There were 4.0% (3/75) patients with bone sarcoma and 4.3% (3/70) patients with STS exhibited high tumor mutational burden (TMB-H) (TMB ≥ 10). There was only one patient with STS exhibited MSI-L, while the remaining cases were microsatellite stable. The positive rate of PD-L1 expression was slightly higher in STS (35.2%) than in bone sarcoma (33.3%), however, this difference did not reach statistical significance. The expression of PD-L1 in STS patients was associated with a poorer prognosis (p = 0.007). Patients with STS had a better prognosis than those with bone sarcoma, but the observed difference did not attain statistical significance (p = 0.21). Amplification of MET and MYC genes were negatively correlated with clinical prognosis in bone tumors (p<0.01). Discussion: In conclusion, bone sarcoma and STS have significantly different clinical and molecular characteristics, suggesting that it is vital to diagnose accurately for clinical treatment. Additionally, comprehensive genetic landscape can provide novel treatment perspectives for primary bone sarcoma and STS. Taking TMB, MSI, PD-L1 expression, and OncoKB definition together into consideration, there are still many patients who have the potential to respond to targeted therapy or immunotherapy.

POTEE mutation as a potential predictive biomarker for immune checkpoint inhibitors in lung adenocarcinoma.

Precise selection of patients who could benefit from immune checkpoint inhibitors (ICIs) is an important challenge for immunotherapy in lung cancer. POTEE (POTE Ankyrin Domain Family Member E) is a member of one primate-specific gene family which have been identified as cancer-related antigens and potential target for immunotherapy of cancer. Here, we investigated the correlation between POTEE mutation and the clinical outcome of ICIs treatment in non-small cell lung cancer (NSCLC). We merged three NSCLC cohorts (n = 165) to assess predictive value of POTEE mutation of immunotherapy efficacy in NSCLC. The prognostic analysis and the potential molecular mechanism exploration were conducted based on the data from The Cancer Genome Atlas (TCGA) database. In the merged cohort, patients with POTEE-mutation (POTEE-Mut) had a significantly higher objective response rate (ORR) (100% vs 27.7%; P < 0.001) and longer progression-free survival (PFS) (P = 0.001; HR 0.08; 95% CI 0.01 - 0.54) compared to patients with POTEE wild-type (POTEE-WT) in NSCLC. Also, patients with POTEE-Mut showed higher ORR (100% vs 27.2%; P < 0.001) and longer PFS (P = 0.001; HR 0.07; 95% CI 0.01 - 0.52) in lung adenocarcinoma (LUAD). POTEE mutation was significantly associated with higher tumor mutational burden (TMB) and higher neoantigen load (NAL), but not with PD-L1 expression in LUAD. Gene set enrichment analyses (GSEA) analysis revealed prominent enrichment of signatures related to DNA repair in POTEE-Mut group (P < 0.001) in LUAD. Our results indicate that POTEE mutation could serve as a potential predictive biomarker for ICIs in LUAD. However, prospective cohort studies are still needed for further validation.

Application and development of noninvasive biomarkers for colorectal cancer screening: a systematic review.

BACKGROUND: Colorectal cancer (CRC) is the second most common cause of cancer-related death (9.4% of the 9.9 million cancer deaths). However, CRC develops slowly, and early detection and intervention can effectively improve the survival rate and quality of life. Although colonoscopy can detect and diagnose CRC, it is unsuitable for CRC screening in average-risk populations. Some commercial kits based on DNA mutation or methylation are approved for screening, but the low sensitivity for advanced adenoma or early-stage CRC would limit the applications. MAIN RESULTS: Recently, researchers have focused on developing noninvasive or minimally invasive, easily accessible biomarkers with higher sensitivity and accuracy for CRC screening. Numerous reports describe advances in biomarkers, including DNA mutations and methylation, mRNA and miRNA, gut microbes, and metabolites, as well as low-throughput multiomics panels. In small cohorts, the specificity and sensitivity improved when fecal immunochemical testing combined with other biomarkers; further verification in large cohorts is expected. In addition, the continuous improvement of laboratory technology has also improved the sensitivity of detection technology, such as PCR, and the application of CRISPR/Cas technology. Besides, artificial intelligence has extensively promoted the mining of biomarkers. Machine learning was performed to construct a diagnosis model for CRC screening based on the cfDNA fragment features from whole-genome sequencing data. In another study, multiomics markers, including cfDNA, epigenetic, and protein signals, were also discovered by machine learning. Finally, advancements in sensor technology promote the applicability of volatile organic compounds in CRC early detection. CONCLUSION: Here, the authors review advances in early detection and screening of CRC based on different biomarker types. Most studies reported optimistic findings based on preliminary research, and prospective clinical studies are ongoing. These promising biomarkers are expected to more accurately identify early-stage patients with CRC and be applied in the future.

Case report: Unique FLT4 variants associated with differential response to anlotinib in angiosarcoma.

Angiosarcoma (AS) is a rare, clinically aggressive tumor with limited treatment options and a poor prognosis. Mutations involving the angiogenesis-related genesTP53, PTPRB, PLCG1, KDR as well as FLT4 amplification have been observed in AS. There is a potential therapeutic value of inhibition of the VEGF pathway against angiosarcoma. Our case first described a patient with two sites of cutaneous angiosarcomas (cASs) that responded differently to anlotinib. And genetic analysis revealed that those two sites had different FLT4 variants, suggesting that FLT4 amplification could be the cause of anlotinib non-response.

Case report: Identification of a novel heterozygous germline ERCC2 mutation in a patient with dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a kind of soft tissue sarcoma, mostly occurs in the trunk, followed by proximal extremities and head and neck. Surgical resection is the most important treatment for DFSP, but the local recurrence rate of DFSP is high. Except reported specific chromosomal tran7slocations occurred in DFSP, the association between DNA repair gene mutations and DFSP still unknown. In this report we found a 19-year-old boy with DFSP carries a novel heterozygous germline ERCC2 mutation, which belongs to the nucleotide excision repair (NER) pathway and genetic defects in ERCC2 may contribute to the cancer susceptibility xeroderma pigmentosum (XP), Cocaine syndrome (CS), and trichothiodystrophy (TTD). Different mutations of the ERCC2 gene can lead to diverse diseases, but there are no targeted therapies. In summary, our results enlarged the mutation spectrum of the DFSP patients. It also provides new insights into genetic counseling and targeted therapeutic strategies for patients with DFSP.

A novel TMTC2-NTRK3 fusion in undifferentiated high-grade pleomorphic sarcoma.

Undifferentiated high-grade pleomorphic sarcoma (UHPS) is a rare soft tissue sarcoma (STS) originated from mesenchyme. UHPS is mostly advanced, aggressive and has poor prognosis. Patients with UHPS tend to have a lower 5-year survival rate than patients with other types of STS. NTRK fusions are commonly found in rare histological tumor types. Among sarcomas, 90% of infantile fibrosarcomas have NTRK fusions. Many other types of sarcomas have also been studied for NTRK fusions. Targeted therapy with NTRK inhibitors, such as Larotrectinib and Entrectinib, leads to response in most patients with NTRK1/2/3 gene fusion-positive tumors. Herein, we present a 68-years old man with UHPS by pathological diagnosis. Next-generation sequencing (NGS) revealed a novel TMTC2-NTRK3 fusion, which was also detected by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). This report broadens the spectrum of NTRK fusions in UHPS and highlights a new target for treatment.