Publications by authors named "Yiyi Xi"

Disclosure of the key events in tumor progress will help us deepen the understanding of tumorigenesis. Here, we present a protocol for multi-regional tissue capture of malignant continuum. We describe steps for preparing tissue sections, laser capture microdissection, and whole-genome library preparation, which enable the concurrent analysis of potential driver events in precancer initiation.

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Esophageal squamous-cell carcinoma (ESCC) is commonly treated with radiotherapy; however, radioresistance hinders its clinical effectiveness, and the underlying mechanism remains elusive. Here, we develop patient-derived xenografts (PDXs) from 19 patients with ESCC to investigate the mechanisms driving radioresistance. Using RNA sequencing, cytokine arrays, and single-cell RNA sequencing, we reveal an enrichment of cancer-associated fibroblast (CAF)-derived collagen type 1 (Col1) and tumor-cell-derived CXCL1 in non-responsive PDXs.

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Esophageal squamous-cell carcinoma (ESCC) develops through multistage epithelial cancer formation, i.e., from normal epithelium, low- and high-grade intraepithelial neoplasia to invasive carcinoma.

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Article Synopsis
  • The study evaluated a new disposable esophagogastroduodenoscopy (EGD) system aimed at preventing cross-infection in medical settings, testing its feasibility and safety in 30 patients during emergencies and surgeries.
  • All procedures using the disposable EGD were successful, with a 100% technical success rate, and no device malfunctions or adverse events reported.
  • The results suggest that the disposable EGD is a safe and effective alternative to traditional EGDs, demonstrating good image quality and efficient procedure times in critical situations.
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Objectives: Adenocarcinoma at the gastroesophageal junction (ACGEJ) refers to a malignant tumor that occurs at the esophagogastric junction. Despite some progress in targeted therapies for HER2, FGFR2, EGFR, MET, Claudin 18.2 and immune checkpoints in ACGEJ tumors, the 5-year survival rate of patients remains poor.

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Unlabelled: Evidence points toward the differentiation state of cells as a marker of cancer risk and progression. Measuring the differentiation state of single cells in a preneoplastic population could thus enable novel strategies for early detection and risk prediction. Recent maps of somatic mutagenesis in normal tissues from young healthy individuals have revealed cancer driver mutations, indicating that these do not correlate well with differentiation state and that other molecular events also contribute to cancer development.

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This study investigates aberrant DNA methylations as potential diagnosis and prognosis markers for esophageal squamous-cell carcinoma (ESCC), which if diagnosed at advanced stages has <30% five-year survival rate. Comparing genome-wide methylation sites of 91 ESCC and matched adjacent normal tissues, we identified 35,577 differentially methylated CpG sites (DMCs) and characterized their distribution patterns. Integrating whole-genome DNA and RNA-sequencing data of the same samples, we found multiple dysregulated transcription factors and ESCC-specific genomic correlates of identified DMCs.

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Esophageal squamous-cell carcinoma (ESCC), one of the most prevalent and lethal malignant disease, has a complex but unknown tumor ecosystem. Here, we investigate the composition of ESCC tumors based on 208,659 single-cell transcriptomes derived from 60 individuals. We identify 8 common expression programs from malignant epithelial cells and discover 42 cell types, including 26 immune cell and 16 nonimmune stromal cell subtypes in the tumor microenvironment (TME), and analyse the interactions between cancer cells and other cells and the interactions among different cell types in the TME.

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Article Synopsis
  • Radiotherapy is commonly used to treat cancer but is often ineffective due to a phenomenon called radioresistance, with unclear underlying mechanisms.
  • In a study focused on esophageal squamous cell carcinoma, researchers found that the protein VAV2 is key to the radioresistance process, being involved in DNA repair mechanisms post-radiation.
  • Overexpressing VAV2 boosts the levels of STAT1, and using a STAT1 inhibitor like Fludarabine increased the effectiveness of radiotherapy in resistant cancer models in mice, suggesting potential strategies to enhance cancer treatment outcomes.
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Adenocarcinoma at the gastroesophageal junction (ACGEJ) has dismal clinical outcomes, and there are currently few specific effective therapies because of limited knowledge on its genomic and transcriptomic alterations. The present study investigates genomic and transcriptomic changes in ACGEJ from Chinese patients and analyzes their drug vulnerabilities and associations with the survival time. Here we show that the major genomic changes of Chinese ACGEJ patients are chromosome instability promoted tumorigenic focal copy-number variations and COSMIC Signature 17-featured single nucleotide variations.

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Esophageal squamous cell carcinoma (ESCC) is prevalent in some geographical regions of the world. ESCC development presents a multistep pathogenic process from inflammation to invasive cancer; however, what is critical in these processes and how they evolve is largely unknown, obstructing early diagnosis and effective treatment. Here, we create a mouse model mimicking human ESCC development and construct a single-cell ESCC developmental atlas.

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: Whole-genome sequencing has identified many amplified genes in esophageal squamous-cell carcinoma (ESCC). This study investigated the role and clinical relevance of these genes in ESCC. : We collected ESCC and non-tumor esophageal tissues from 225 individuals who underwent surgery.

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Esophageal squamous-cell carcinoma (ESCC) is one of the most lethal malignancies in the world and occurs at particularly higher frequency in China. While several genome-wide association studies (GWAS) of germline variants and whole-genome or whole-exome sequencing studies of somatic mutations in ESCC have been published, there is no comprehensive database publically available for this cancer. Here, we developed the Chinese Cancer Genomic Database-Esophageal Squamous Cell Carcinoma (CCGD-ESCC) database, which contains the associations of 69,593 single nucleotide polymorphisms (SNPs) with ESCC risk in 2022 cases and 2039 controls, survival time of 1006 ESCC patients (survival GWAS) and gene expression (expression quantitative trait loci, eQTL) in 94 ESCC patients.

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