Cancer-associated fibroblasts (CAFs) are principal determinants of pancreatic ductal adenocarcinoma (PDAC) progression. CAFs can shape tumor behavior via multiple pathways, underscoring the need for a complete understanding of the regulatory mechanisms that govern CAF function. Here, we identified N6-methyladenosine (m6A) remodeling as a hallmark of CAF activation and defined a critical role for the m6A demethylase ALKBH5 in PDAC metastasis. Activated CAFs exhibited a global reduction in m6A abundance, with ALKBH5 emerging as a key regulator of the CAF epitranscriptome. Functionally, CAF-derived ALKBH5 enhanced pancreatic cancer cell migration and invasion in vitro and promoted epithelial-mesenchymal transition-associated gene expression in tumor cells in an m6A-dependent manner. Orthotopic co-implantation models and host genetic ablation models demonstrated that ALKBH5 plays a critical role in metastatic dissemination, with minimal impact on primary tumor growth. Mechanistically, ALKBH5 enhanced the m6A-dependent translation of HSF1 in CAFs, at least in part by relieving IGF2BP3-associated translational constraints. Elevated HSF1 subsequently activated LIF transcription through distal enhancer elements, establishing an ALKBH5-HSF1-LIF signaling axis that mediated the pro-metastatic CAF-tumor cell communication. Clinically, enrichment of ALKBH5⁺HSF1⁺ CAFs independently predicted poor prognosis and was preferentially observed in metastatic PDAC. Collectively, these findings uncover a CAF-intrinsic epitranscriptomic program that drives PDAC metastasis and highlight stromal m6A regulation as a potential therapeutic vulnerability.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a highly immunosuppressive and desmoplastic tumor microenvironment (TME) that limits the efficacy of immunotherapy. However, the evolution of this immunosuppressive TME and the underlying mechanisms remain incompletely understood. Here, we construct a dynamic single-cell atlas spanning uninvolved adjacent pancreatic tissue (UNIN), intraductal papillary mucinous neoplasm (IPMN), and PDAC. We confirm the stepwise establishment of an immunosuppressive milieu, accompanied by the emergence of LRRC15+ fibroblasts as determinants. Functional assays further identify tumor-derived LAMB3 as a regulator of LRRC15+ fibroblast differentiation. Mechanistically, LAMB3 promotes FOSL2-dependent transcriptional activation of LRRC15 through the ITGB1/FAK/MAPK signaling axis, ultimately suppressing T cell cytotoxicity. Orthotopic models reveal that LAMB3 overexpression increases the LRRC15 positive area and impairs T cell cytotoxicity, whereas FAK inhibition partially reverses these effects. In parallel, LAMB3 knockdown reduces the LRRC15 positive area and improves the efficacy of PD-1 blockade. Moreover, glycolytic reprogramming in PDAC ductal cells upregulates LAMB3 expression and correlates with increased LRRC15+ fibroblast enrichment. Clinically, co-enrichment of LAMB3+ PDAC ductal cells and LRRC15+ fibroblasts is associated with inferior overall survival. Collectively, our findings define a dynamic ductal-fibroblast-immune multicellular axis underlying PDAC pathogenesis and provide insights into potential therapeutic strategies.

Background Tertiary lymphoid structures (TLSs) are organized immune aggregates that are associated with favorable outcomes in several solid tumors, but their role in endometrial cancer (EC) remains unexplored. Methods We retrospectively analyzed 93 patients with EC who underwent surgery in a single team at Peking Union Medical College Hospital. TLSs were identified by hematoxylin‒eosin staining and immunohistochemical or immunofluorescence analyses for CD20, CD8, CD4, CXCL13, and CXCR5 expression. Associations with clinicopathological variables and survival were evaluated. Results TLSs were detected in 35 patients (37.6%). They consisted of dense CD20⁺ B cell clusters admixed with CD8⁺ and CD4⁺ T cells and exhibited specific upregulation of the CXCL13/CXCR5 axis. CD20⁺ B cell density was positively correlated with the number of TLSs and with CD8⁺ and CD4⁺ T-cell infiltration. During a median follow-up of 58.1 months, patients with TLSs had significantly improved progression-free survival (PFS, P = 0.032) and overall survival (OS, P = 0.046). Multivariate analysis revealed the presence of TLSs as an independent predictor of reduced recurrence risk (HR 0.125, 95% CI 0.024–0.667; P = 0.015). High coexpression of CD20 and CD8 was associated with the best PFS (P = 0.028), whereas high CD20 expression with low CD4 expression was correlated with the best OS (P = 0.048). Conclusions TLSs are present in patients with EC and confer a significant survival advantage. These findings highlight B-cell-mediated immunity and the CXCL13/CXCR5 axis as promising prognostic biomarkers and potential therapeutic targets in this disease.

The limited effectiveness of T cell-based immune checkpoint blockade (ICB) therapy in most patients with pancreatic ductal adenocarcinoma (PDAC) is largely due to poor CD8+ T cell infiltration and a highly immunosuppressive microenvironment driven by excessive myeloid cell accumulation. This highlights the urgent need for new immunotherapy targets and strategies. In this study, an identified pro-cancer factor, cancer cell-derived sialylated IgG (SIA-IgG), is found to be significantly overexpressed in pancreatic cancer cells. SIA-IgG inhibits macrophage phagocytosis and induces an M2-like immunosuppressive phenotype through interactions with Siglec-7/9/10. SIA-IgG and TGF-β1, a key immunosuppressive factor, reinforce each other in a positive feedback loop, promoting immune evasion in PDAC. Blocking SIA-IgG with specific monoclonal antibodies shows significant therapeutic potential through reversal of PDAC’s immunosuppressive microenvironment. Our findings identify the SIA-IgG/Siglec axis as an immunotherapeutic target for PDAC, offering a feasible approach for the development of immunotherapeutic strategies.

HER2-targeted therapy is increasingly used in colorectal cancer (CRC). However, discrepancies between conventional detection methods (immunohistochemistry [IHC]/fluorescence in situ hybridization [FISH]) and next-generation sequencing (NGS) remain to be elucidated. Furthermore, the impact of spatial intratumoral heterogeneity (SIH) in HER2 overexpression on both the methodological concordance and therapeutic efficacy is still poorly understood. Two consecutive retrospective cohorts from Peking Union Medical College Hospital (2018–2024) were analyzed. In the NGS cohort (n = 1,343), HER2-amplified cases were identified based on NGS-derived gene copy number (GCN), and their clinicopathological and molecular features were characterized using stage-matched HER2-non-amplified controls. In the IHC cohort (n = 3,585), spatial HER2 expression heterogeneity was comprehensively assessed. Finally, treatment outcomes were reviewed in four HER2-amplified patients who received anti-HER2 therapy. HER2 amplification was detected in 2.53

C-Myc overexpression is an important molecular hallmark of pancreatic ductal adenocarcinoma (PDAC), but directly targeting c-Myc is extremely challenging. Identifying key upstream factors involved in c-Myc overexpression provides promising indirect targets for c-Myc. Public transcriptomic and clinical datasets, including TCGA, GEO, were integrated to identify c-Myc-associated long noncoding RNAs in PDAC, with LINC01963 selected for further investigation. The functional roles of LINC01963 were validated using human PDAC cell lines and in vivo proliferation models. The molecular mechanisms underlying c-Myc regulation by LINC01963 were explored using RNA pull-down, RIP-seq, RIP-qPCR, Co-IP, mass spectrometry, ubiquitination assays, truncation and site-directed mutagenesis analyses, and dual-luciferase reporter assays. Survival associations were evaluated using Kaplan–Meier analysis and Cox proportional hazards regression. Here, the long noncoding RNAs (lncRNAs) highly expressed in PDAC and significantly correlated with c-Myc expression were identified using RNA sequencing datasets. Among them, LINC01963 was found to interact with c-Myc, as confirmed by RNA pull-down and RIP-qPCR assays. Furthermore, high LINC01963 expression was correlated with poor PDAC prognosis, and functional studies demonstrated that its knockdown inhibited PDAC cell proliferation and xenograft tumor growth. Mechanistic studies identified LINC01963 as a key regulator of c-Myc stability, consequently affecting cell cycle through the c-Myc/p21-related signaling pathways. Further investigation revealed that LINC01963 enhanced N6-methyladenosine (m⁶A) modification of c-Myc mRNA by protecting methyltransferase-like 3 (METTL3) protein from KDM1B-mediated K48-linked ubiquitination and proteasomal degradation. Intriguingly, LINC01963 also stabilized c-Myc mRNA by facilitating the formation of a ternary complex with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) and m⁶A-modified c-Myc. Our study reveals that LINC01963 promotes PDAC tumorigenesis through METTL3/IGF2BP2 axis-coordinated regulation of c-Myc, suggesting a new strategy for indirectly targeting c-Myc.

Neurotrophic tyrosine receptor kinase (NTRK) fusions are crucial in tumorigenesis and in guiding targeted therapy with TRK inhibitors. However, their rarity, fusion heterogeneity, and limitations of conventional pan-TRK immunohistochemistry (IHC) impede accurate clinical detection. This multicenter retrospective study analyzed 374 next-generation sequencing/fluorescence in situ hybridization-validated samples (195 NTRK positive and 179 NTRK negative) collected from 12 Chinese centers to investigate fusion heterogeneity and refine the interpretation of pan-TRK IHC. We developed an amplification protocol by combining the traditional pan-TRK IHC (EPR17341) with the OptiView Amplification Kit and established new interpretation criteria. A total of 40 solid tumor types were included, and 23 unique fusion partners were identified. Papillary thyroid cancer was the most common NTRK-positive tumor (49.74%) and harbored all 3 NTRK subtypes. Among NTRK-positive samples, NTRK3 (74.87%) was the most prevalent subtype, followed by NTRK1 (23.59%). ETS variant transcription factor 6 (ETV6) was the most frequent fusion partner identified in 122 of 195 cases. It was uniquely shared across all 3 NTRK subtypes, with its fusion to NTRK1 being reported for the first time. NTRK1 and NTRK3 exhibited marked fusion partner specificity, with no overlap in their associated partners except for ETV6. The optimized pan-TRK IHC protocol significantly improved staining efficiency by enhancing intensity and clarity. Consequently, the newly established criteria (cytoplasmic intensity ≥1 in ≥50% of tumor cells or any nuclear intensity ≥1) exhibited outstanding detection performance, achieving an overall sensitivity of 94.36% and increasing specificity to 79.89% compared with 60.22% under the conventional protocol. Particularly, the detection sensitivity for NTRK3 fusions was significantly enhanced and reached 95.89%. This study contributes to clarifying NTRK fusion distribution in patients and validates a standardized, sensitive pan-TRK IHC strategy for clinical screening.

Accurate histopathological evaluation of pancreatic ductal adenocarcinoma (PDAC), including primary tumor lesions and lymph node metastases, is critical for prognostic evaluation and personalized therapeutic strategies. Distinct from other solid tumors, PDAC presents unique diagnostic challenges owing to its extensive desmoplasia, unclear tumor boundary, and difficulty in differentiating from chronic pancreatitis. These characteristics not only complicate pathological diagnosis but also hinder the acquisition of pixel-level annotations required for training computational pathology models. In this study, we present PANseg, a multiscale weakly supervised deep learning framework for PDAC segmentation, trained and tested on 368 whole-slide images (WSIs) from 208 patients across 2 independent centers. Using only image-level labels (2048 × 2048 pixels), PANseg achieved comparable performance with fully supervised baseline (FSB) across the internal test set 1 (17 patients/58 WSIs; PANseg area under the receiver operating characteristic curve [AUROC]: 0.969 vs FSB AUROC: 0.968), internal test set 2 (40 patients/44 WSIs; PANseg AUROC: 0.991 vs FSB AUROC: 0.980), and external test set (20 patients/20 WSIs; PANseg AUROC: 0.950 vs FSB AUROC: 0.958). Moreover, the model demonstrated considerable generalizability with previously unseen sample types, attaining AUROCs of 0.878 on fresh-frozen specimens (20 patients/20 WSIs) and 0.821 on biopsy sections (20 patients/20 WSIs). In lymph node metastasis detection, PANseg augmented the diagnostic accuracy of 6 pathologists from 0.888 to 0.961, while reducing the average diagnostic time by 32.6% (72.0 vs 48.5 minutes). This study demonstrates that our weakly supervised model can achieve expert-level segmentation performance and substantially reduce annotation burden. The clinical implementation of PANseg holds great potential in enhancing diagnostic precision and workflow efficiency in the routine histopathological assessment of PDAC.

A 35-year-old man was diagnosed with tumor-induced osteomalacia (TIO) caused by a phosphaturic mesenchymal tumor (PMT) in the right maxilla. The patient underwent CT-guided cryoablation at our institution, which successfully eradicated the tumor while preserving the pulpal vitality of adjacent teeth. We describe the clinical history, physical examination findings, laboratory tests, functional imaging, and follow-up protocol for evaluating treatment outcomes. Cryoablation demonstrated therapeutic efficacy through symptomatic relief, normalization of serum phosphorus levels, and maintenance of pulpal vitality, as well as preservation of neighboring natural teeth. Although extensive surgical resection remains the standard treatment for PMTs in jaw bones, image-guided cryoablation presents a minimally invasive alternative. This approach offers significant advantages in preserving occlusal anatomy and functionality, marking a paradigm shift in TIO management.

BACKGROUND:Metabolic reprogramming plays a pivotal role in cancer progression, contributing to substantial intratumour heterogeneity and influencing tumour behaviour. However, a systematic characterization of metabolic heterogeneity across multiple cancer types at the single-cell level remains limited. METHODS:We integrated 296 tumour and normal samples spanning six common cancer types to construct a single-cell compendium of metabolic gene expression profiles and identify cell type-specific metabolic properties and reprogramming patterns. A computational approach based on non-negative matrix factorization (NMF) was utilised to identify metabolic meta-programs (MMPs) showing intratumour heterogeneity. In-vitro cell experiments were conducted to confirm the associations between MMPs and chemotherapy resistance, as well as the function of key metabolic regulators. Survival analyses were performed to assess clinical relevance of cellular metabolic properties. FINDINGS:Our analysis revealed shared glycolysis upregulation and divergent regulation of citric acid cycle across different cell types. In malignant cells, we identified a colorectal cancer-specific MMP associated with resistance to the cuproptosis inducer elesclomol, validated through in-vitro cell experiments. Furthermore, our findings enabled the stratification of patients into distinct prognostic subtypes based on metabolic properties of specific cell types, such as myeloid cells. INTERPRETATION:This study presents a nuanced understanding of multilayered metabolic heterogeneity, offering valuable insights into potential personalized therapies targeting tumour metabolism. FUNDING:National Key Research and Development Program of China (2021YFA1300601). National Natural Science Foundation of China (key grants 82030081 and 81874235). The Shenzhen High-level Hospital Construction Fund and Shenzhen Basic Research Key Project (JCYJ20220818102811024). The Lam Chung Nin Foundation for Systems Biomedicine.

e15160 Background: Using IHC to screen NTRK+ patients, followed by NGS confirmation, is a strategy recommended by ESMO guidelines. However, the current IHC staining protocol (Protocol) and cutoff value (CV) are suboptimal, resulting in limited screening performance. This study aims to optimize the Protocol and redefine the CV to improve the efficacy of pan-TRK IHC in screening NTRK fusions. Methods: 126 NTRK+ and 162 NTRK- solid tumor samples (spls), previously confirmed by NGS and/or FISH, were collected retrospectively from 12 hospitals across China in 2023. All spls were stained with VENTANA pan-TRK IHC assay by using two different Protocols: 1) the conventional one recommended by the manufacturer's instruction and 2) an amplification one that included additional amplification steps to enhance the staining. The IHC stained spls were interpreted based on the manufacturer's instruction, and the results were analyzed to calculate the CVs. The sensitivity, specificity, accuracy, PPV, and NPV based on these CVs and the CV reported in the literature were calculated. Results: 126 NTRK+ spls involve 25 fusion-partner types and 23 tumor types. IHC showed 35 NTRK- spls without staining, and 253 spls (126NTRK+/127NTRK-) stained. The staining predominantly localized to the cytoplasm and nucleus (132 cytoplasmic positive, 105 cytoplasmic and nuclear positive). Due to the limited samples with membrane staining, only CVs for cytoplasmic and nuclear staining were defined. In order to enhance the sensitivity and feasibility of the pan-TRK IHC assay in NTRK+ screening, the statistically calculated CVs were adjusted, and we recommended using the following CVs in clinical practice: 1) ≥1 intensity of cytoplasmic staining in ≥50% of tumor cells and/or 2) ≥1 intensity of nuclear staining in any percentage of tumor cells. Compared with the statistically calculated CVs, although the accuracy of the recommended CVs was slightly reduced (87.5% vs 93.75%), the sensitivity was improved (94.44% vs 89.68%). The sensitivity and specificity of the recommended CVs were higher than that of the previously reported CV (≥1%): sensitivity (94.44% vs. 87.9%) and specificity (82.1% vs. 81.1%). Conclusions: The pan-TRK IHC assay demonstrated high sensitivity while maintaining good specificity and accuracy, improving screening and enrichment efficacy for identifying NTRK fusions in solid tumors by utilizing the amplification protocol and the recommended CVs. Clinical trial information: ChiCTR2200066850 . [Table: see text]

Pancreatic intraepithelial neoplasias (PanINs) are the most common precursors of pancreatic cancer, but their small size and inaccessibility in humans make them challenging to study1. Critically, the number, dimensions and connectivity of human PanINs remain largely unknown, precluding important insights into early cancer development. Here, we provide a microanatomical survey of human PanINs by analysing 46 large samples of grossly normal human pancreas with a machine-learning pipeline for quantitative 3D histological reconstruction at single-cell resolution. To elucidate genetic relationships between and within PanINs, we developed a workflow in which 3D modelling guides multi-region microdissection and targeted and whole-exome sequencing. From these samples, we calculated a mean burden of 13 PanINs per cm3 and extrapolated that the normal intact adult pancreas harbours hundreds of PanINs, almost all with oncogenic KRAS hotspot mutations. We found that most PanINs originate as independent clones with distinct somatic mutation profiles. Some spatially continuous PanINs were found to contain multiple KRAS mutations; computational and in situ analyses demonstrated that different KRAS mutations localize to distinct cell subpopulations within these neoplasms, indicating their polyclonal origins. The extensive multifocality and genetic heterogeneity of PanINs raises important questions about mechanisms that drive precancer initiation and confer differential progression risk in the human pancreas. This detailed 3D genomic mapping of molecular alterations in human PanINs provides an empirical foundation for early detection and rational interception of pancreatic cancer. Quantitative multimodal 3D reconstruction of human pancreatic tissue at single-cell resolution reveals a high burden of multifocal, genetically heterogeneous pancreatic intraepithelial neoplasias in the normal adult pancreas.

Pancreatic intraepithelial neoplasia (PanIN) is a precursor to pancreatic cancer and represents a critical opportunity for cancer interception. However, the number, size, shape, and connectivity of PanINs in human pancreatic tissue samples are largely unknown. In this study, we quantitatively assessed human PanINs using CODA, a novel machine-learning pipeline for 3D image analysis that generates quantifiable models of large pieces of human pancreas with single-cell resolution. Using a cohort of 38 large slabs of grossly normal human pancreas from surgical resection specimens, we identified striking multifocality of PanINs, with a mean burden of 13 spatially separate PanINs per cm3 of sampled tissue. Extrapolating this burden to the entire pancreas suggested a median of approximately 1000 PanINs in an entire pancreas. In order to better understand the clonal relationships within and between PanINs, we developed a pipeline for CODA-guided multi-region genomic analysis of PanINs, including targeted and whole exome sequencing. Multi-region assessment of 37 PanINs from eight additional human pancreatic tissue slabs revealed that almost all PanINs contained hotspot mutations in the oncogene KRAS, but no gene other than KRAS was altered in more than 20% of the analyzed PanINs. PanINs contained a mean of 13 somatic mutations per region when analyzed by whole exome sequencing. The majority of analyzed PanINs originated from independent clonal events, with distinct somatic mutation profiles between PanINs in the same tissue slab. A subset of the analyzed PanINs contained multiple KRAS mutations, suggesting a polyclonal origin even in PanINs that are contiguous by rigorous 3D assessment. This study leverages a novel 3D genomic mapping approach to describe, for the first time, the spatial and genetic multifocality of human PanINs, providing important insights into the initiation and progression of pancreatic neoplasia.

Phosphaturic mesenchymal tumors (PMTs) are rare neoplasms of soft tissue or bone. Although previous studies revealed that approximately 50% of PMTs harbor FN1::FGFR1 fusions, the molecular mechanisms in the remaining cases are largely unknown. In this study, fusion genes were investigated using RNA-based next-generation sequencing in 76 retrospectively collected PMTs. Novel fusions were validated with Sanger sequencing and fluorescence in situ hybridization. Fusion genes were detected in 52/76 (68.4%) PMTs, and 43/76 (56.6%) harbored FN1::FGFR1 fusions. Fusion transcripts and breakpoints of the FN1::FGFR1 fusions were diverse. The most common fusion transcript was between exon 20 of FN1 and exon 9 of FGFR1 (7/43, 16.3%). The most upstream breakpoint of the FN1 gene was located at the 3' end of exon 12, and the most downstream breakpoint of the FGFR1 gene was at the 5' end of exon 9, suggesting the inessential nature of the third fibronectin-type domain of FN1 and the necessity of the transmembrane domain of FGFR1 in the FN1::FGFR1 fusion protein, respectively. Moreover, the reciprocal FGFR1::FN1 fusions, which had not been identified in previous studies, were detected in 18.6% (8/43) of FN1::FGFR1 fusion-positive PMTs. Novel fusions were identified in 6/76 (7.9%) FN1::FGFR1 fusion-negative PMTs, including 2 involving FGFR: FGFR1::USP33 (1/76, 1.3%) and FGFR1::TLN1 (1/76, 1.3%). Other novel fusions identified were the PDGFRA::USP35 (1/76, 1.3%), SPTBN1::YWHAQ (1/76, 1.3%), GTF2I::RALGPS1 (1/76, 1.3%), and LTBP1::VWA8 (1/76, 1.3%) fusions. In addition to these novel fusions, FN1::FGFR2 (1/76, 1.3%), NIPBL::BEND2 (1/76, 1.3%), and KIAA1549::BRAF fusions (1/76, 1.3%) were also identified in FN1::FGFR1-negative cases arising from the thigh, ilium, and acetabulum, respectively. The frequency of oncogenic fusions was significantly higher (P = .012) in tumors derived from extremities (29/35, 82.9%) compared with other locations (23/41, 56.1%). No significant correlation was identified between fusions and recurrence (P = .786). In conclusion, we report fusion transcripts and breakpoints of FN1::FGFR1 in PMTs in detail, providing insights into fusion protein functions. We also revealed that a considerable proportion of PMTs without FN1::FGFR1 fusion carried novel fusions, providing further insight into the genetic basis of PMTs.

Pancreatic stellate cells (PSCs) are crucial for metabolism and disease progression in pancreatic ductal adenocarcinoma (PDAC). However, detailed mechanisms of PSCs in glutamine (Gln) metabolism and tumor-stromal metabolic interactions have not been well clarified. Here we showed that tumor tissues displayed Gln deficiency in orthotopic PDAC models. Single-cell RNA sequencing analysis revealed metabolic heterogeneity in PDAC, with significantly higher expression of Gln catabolism pathway in stromal cells. Significantly higher glutamine synthetase (GS) protein expression was further validated in human tissues and cells. Elevated GS levels in tumor and stroma were independently prognostic of poorer prognosis in PDAC patients. Gln secreted by PSCs increased basal oxygen consumption rate in PCCs. Depletion of GS in PSCs significantly decreased PCCs proliferation in vitro and in vivo. Mechanistically, activation of Wnt signaling induced directly binding of β-catenin/TCF7 complex to GS promoter region and upregulated GS expression. Rescue experiments testified that GS overexpression recovered β-catenin knockdown-mediated function on Gln synthesis and tumor-promoting ability of PSCs. Overall, these findings identify the Wnt/β-catenin/TCF7/GS-mediated growth-promoting effect of PSCs and provide new insights into stromal Gln metabolism, which may offer novel therapeutic strategies for PDAC.

The poor prognosis of pancreatic ductal adenocarcinoma (PDAC) is associated with the tumour heterogeneity. To explore intra- and inter-tumoural heterogeneity in PDAC, we analysed the multi-omics profiles of 61 PDAC lesion samples, along with the matched pancreatic normal tissue samples, from 19 PDAC patients. Haematoxylin and Eosin (H&E) staining revealed that diversely differentiated lesions coexisted both within and across individual tumours. Whole exome sequencing (WES) of samples from multi-region revealed diverse types of mutations in diverse genes between cancer cells within a tumour and between tumours from different individuals. The copy number variation (CNV) analysis also showed that PDAC exhibited intra- and inter-tumoural heterogeneity in CNV and that high average CNV burden was associated poor prognosis of the patients. Phylogenetic tree analysis and clonality/timing analysis of mutations displayed diverse evolutionary pathways and spatiotemporal characteristics of genomic alterations between different lesions from the same or different tumours. Hierarchical clustering analysis illustrated higher inter-tumoural heterogeneity than intra-tumoural heterogeneity of PDAC at the transcriptional levels as lesions from the same patients are grouped into a single cluster. Immune marker genes are differentially expressed in different regions and tumour samples as shown by tumour microenvironment (TME) analysis. TME appeared to be more heterogeneous than tumour cells in the same patient. Lesion-specific differentially methylated regions (DMRs) were identified by methylated DNA immunoprecipitation sequencing (MeDIP-seq). Furthermore, the integration analysis of multi-omics data showed that the mRNA levels of some genes, such as PLCB4, were significantly correlated with the gene copy numbers. The mRNA expressions of potential PDAC biomarkers ZNF521 and KDM6A were correlated with copy number alteration and methylation, respectively. Taken together, our results provide a comprehensive view of molecular heterogeneity and evolutionary trajectories of PDAC and may guide personalised treatment strategies in PDAC therapy.

Objective To investigate the clinical characteristics and survival outcomes of patients with malignant transformation arising from ovarian mature cystic teratoma (MT-MCT). Methods This retrospective study included patients with ovarian MCTs at Peking Union Medical College Hospital (PUMCH) during 1990.01-2020.12. When the pathologic histology was MT-MCT, detailed information was collected. Results Overall, 7229 ovarian MCT patients and 22 patients with MT-MCT were enrolled. The rate of malignant transformation of all ovarian MCTs was 0.30%. Most patients with MT-MCT were 51 (21–75) years old, and the tumor mass size was 10 (3–30) cm. The typical clinical symptoms were mainly abdominal pain and distension. The levels of tumor markers were elevated on preoperative examination. Early diagnosis could be made by ultrasonic examination, pelvic enhanced MRI and CT. Most patients underwent debulking surgery and adjuvant chemotherapy. The most common histological type to exhibit malignant transformation was squamous cell carcinoma (59.1%), followed by adenocarcinoma (13.6%), carcinoid (9.1%), and borderline tumor (18.2%). The 5-year RFS and OS rates were 54.5% and 81.8%, respectively. Patients with FIGO stage I had the best RFS (P=0.047) and OS (P=0.018), followed by those with FIGO stage II-IV. Conclusion MT-MCTs mainly occur in elderly females, are rare and have a poor prognosis. Advanced FIGO stage is a risk factor for survival. Although there is no standard treatment, cytoreductive debulking surgery and adjuvant chemotherapy could be considered. Perimenopausal and menopausal women with MCT should receive surgical treatment.

目的 探讨肺小细胞癌(small cell lung cancer,SCLC)中神经营养因子受体酪氨酸激酶(NTRK)的基因融合及基因变异情况.方法 回顾性收集北京协和医院2008-2021年间SCLC病例组织标本58例,并收集相应临床病理资料;采用免疫组化(immunohistochemistry,IHC)染色方法检测NTRK融合蛋白表达情况,对经IHC染色鉴定为NTRK阳性的病例,进一步采用荧光原位杂交(FISH)方法进行验证.此外,通过包含638基因的靶向测序检测58例标本的NTRK突变及融合变异.结果 本研究中共纳入58例SCLC病例.IHC检测结果提示6例(10.3％)样本NTRK阳性表达,但FISH及靶向测序检均未在此队列中发现NTRK融合基因;靶向测序结果提示11例样本(11/58,19.0％)检出12个NTRK突变,其中1例样本为NTRK1与NTRK3共突变,其余为单一NTRK突变,NTRK3突变6例(10.3％)、NTRK1突变3例(5.1％)、NTRK2突变1例(1.7％);2例伴有NTRK突变病例为IHC阳性表达.结论 本组SCLC缺乏NTRK基因融合,NTRK基因突变率为19％,通过IHC检测方法在SCLC中筛查NTRK融合蛋白表达具有较高的假阳性率,需要采用其他检测平台进行复验.

目的 探讨肺小细胞癌(SCLC)中免疫治疗分子标志物程序性死亡配体1(PD-L1)及肿瘤突变负荷(TMB)与临床病理特征的相关性及预后分析.方法 回顾性收集北京协和医院2008-2018年间SCLC病例组织标本50例,并收集相应临床病理资料;采用免疫组织化学(IHC)染色检测PD-L1在肿瘤细胞和肿瘤浸润淋巴细胞(TILs)的表达,通过包含638基因的靶向测序检测TMB,分析TMB与PD-L1表达的相关性.通过生存分析探究PD-L1表达和TMB的预后意义.结果 本研究中共纳入50例SCLC病例,16例为活检标本,34例为手术标本.5例病例PD-L1表达在肿瘤细胞中呈阳性,45例在TILs中阳性.通过临床病理分析发现,PD-L1肿瘤细胞阳性表达与年龄呈正相关(P=0.020);生存分析发现,TILs的PD-L1表达评分≥85％时,患者无进展生存期(PFS)更短(P=0.042).当以5.2突变/Mb为界值将TMB分组分析时,TMB与PD-L1在肿瘤细胞中的表达相关(P=0.048).结论 肿瘤细胞PD-L1阳性表达患者多为年轻的SCLC,PD-L1在TILs中的表达与SCLC患者PFS呈正相关;TMB以5.2突变/Mb为界值时与PD-L1在肿瘤细胞中表达相关.SCLC相关分子标志物检测对免疫治疗具有指导作用,并对预后具有预测意义.