Immune checkpoint inhibitors (ICI) are in standard use for the treatment of many kinds of metastatic tumor. Their use before surgery to prolong event-free and overall survival (EFS, OS) has been studied in recent years. This review is based on clinically relevant studies published since 2018 on the preoperative use of ICI for four tumor entities: breast cancer, non-small cell lung cancer (NSCLC), colorectal cancer, and esophagogastric adenocarcinoma. The studies were identified by a selective search in PubMed. In addition, abstracts from international conference presentations were evaluated. The approved, standard perioperative treatment of triple-negative breast cancer of stage IIa and above is with durvalumab (an ICI) combined with chemotherapy for one year. This improved the 5-year EFS by 9% (81.2% vs. 72.2%; HR = 0.65) and the overall survival rate by 5% (86.6% vs. 81.7%; HR = 0.66). In NSCLC, the addition of an ICI to preoperative chemotherapy increased 2-year EFS by approximately 11% in stage II or III (63.3% vs. 52.4%; HR = 0.68), according to the largest trial that has been published to date. The addition of durvalumab to perioperative chemotherapy for stage II or III esophagogastric adenocarcinoma increased the 2-year EFS by 8% (67% vs. 59%; HR = 0.71). Approval for this indication is expected. In colorectal carcinoma with microsatellite instability, neoadjuvant ICI therapy for 1-6 months often led to clinical and/or histological complete remission. In view of the high remission rates (50%-100%), patients with rectal carcinoma may be spared surgery and the particular risks it entails. For some types of tumor, neoadjuvant ICI therapy is standard and/or about to be approved. Special care must be taken in managing ICI toxicity. In view of the adverse effects and cost of ICI, it will be important to identify biomarkers for a higher likelihood of benefit.

Microsatellite instability (MSI), caused by impaired mismatch repair (MMR), has gained prominence as a biomarker predicting response to immune checkpoint inhibitors in various cancers. MSI-high (MSI-H) tumours exhibit widespread instability across multiple microsatellite loci and are well-characterized. In contrast, low-level microsatellite instability (MSI-L)-marked by instability at a low number of loci-is poorly understood and its biological relevance remains controversial. MSI-L has often been grouped together with microsatellite stable (MSS) tumours, given the lack of consistent molecular distinctions. However, some studies, particularly in colorectal and gastric cancers, have reported that MSI-L correlates with distinct clinical and molecular features, including poorer prognosis, increased tumour mutational burden (TMB) following chemotherapy, and better response to platinum/5-fluorouracil-based neoadjuvant chemotherapy. Notably, these associations frequently involve instability at dinucleotide repeat markers, hinting at a specific subset of MSI-L. Moreover, recent data provide initial evidence that MSI-L may be associated with subtle alterations of genes involved in DNA damage tolerance pathways. This review aims to clarify the current understanding of MSI-L by (a) comparing diagnostic methods and their influence on MSI-L classification, (b) summarizing clinical and molecular associations of MSI-L specifically in gastric and colorectal cancer, (c) highlighting new aspects regarding potential mechanisms underlying MSI-L, focusing on the particular unstable marker and a possible role of the DNA damage tolerance pathways, and (d) discussing whether MSI-L, particularly defined by dinucleotide repeat instability, may serve as a marker for therapeutic vulnerability.

Pancreatic cancer (PC), predominantly pancreatic ductal adenocarcinoma, remains one of the most lethal malignancies, largely due to late diagnosis and intrinsic resistance to conventional therapies. In recent years, mismatch repair deficiency (dMMR) and microsatellite instability-high (MSI-H) have emerged as clinically actionable biomarkers in a small but distinct subset of PC, accounting for approximately 1-2% of cases. These tumors display unique molecular characteristics, including a high prevalence of wild-type KRAS and TP53, elevated tumor mutational burden, and recurrent kinase fusions, which together confer enhanced immunogenicity and increased sensitivity to immune checkpoint inhibitors (ICIs). In addition to their therapeutic relevance, dMMR/MSI-H status has important diagnostic implications for the identification of Lynch syndrome-associated pancreatic cancers, informing genetic counseling and familial risk assessment. This review summarizes current understanding of the molecular basis of mismatch repair deficiency and microsatellite instability in PC, evaluates available diagnostic approaches such as immunohistochemistry, polymerase chain reaction, and next-generation sequencing, and discusses the prognostic and predictive significance of dMMR/MSI-H status. Emerging clinical evidence supporting the use of ICIs in selected patients across neoadjuvant, adjuvant, and advanced disease settings is also reviewed, along with challenges related to assay discordance, tumor heterogeneity, and immunotherapy resistance. Finally, future directions are highlighted, emphasizing the need for standardized testing algorithms, integration of multi-omics and spatial profiling technologies, and prospective clinical studies to optimize precision treatment strategies for this rare but clinically meaningful subtype of pancreatic cancer.

People with HIV (PWH) remain underrepresented in molecular studies and clinical trials of diffuse large B-cell lymphoma (DLBCL), despite DLBCL being a leading cause of cancer-related death in this population. We performed whole-exome sequencing on 30 DLBCL tumors (24 with paired germline) from a Malawian cohort including both HIV-positive (HIV+) and HIV-negative (HIV-) individuals. KMT2D, BIRC6, TP53, and ARID1A were among the most frequently mutated genes. Compared to HIV- DLBCL, the HIV+ DLBCL tumors in this cohort were enriched for mutations in KMT2D, among others, and prior antiretroviral therapy associated with increased tumor mutational burden (TMB) and neoantigen load. Five HIV+ DLBCL tumors exhibited microsatellite instability (MSI), each with strong contributions from mutational signatures related to DNA repair. Furthermore, ARID1A mutations were observed in several MSI samples and in tumors with MSH2 loss. Integration with a published HIV+ DLBCL dataset revealed recurrent driver mutations including LILRB1 p.R30S, MYD88 p.S206C and p.S238N, and NRAS p.Q61K, as well as PTEN mutation as negatively prognostic. Together, these results highlight distinct tumorigenic mechanisms in HIV+ DLBCL and underscore the need for mutational profiling of HIV+ DLBCL cohorts worldwide to identify biomarkers and therapeutic targets.

While the prevalence of microsatellite instability (MSI) is low in the whole head and neck squamous cell carcinoma (HNSCC) population, it has been suggested to be more prominent in tumors of non-smokers. Therefore, the goal of this study was to determine the presence of MSI in a cohort of well-defined HNSCC of non-smokers and non-drinkers (NSND). Clinical characteristics and tumor tissue of 119 NSND with HNSCC were retrospectively collected and analyzed for MLH1, PMS2, MSH2, and MSH6 protein expression on tissue microarrays (TMA). In case of negative staining for one of these mismatch repair proteins in the TMA cores, immunohistochemistry (IHC) was repeated on a whole slide section and additional molecular analyses were performed using polymerase chain reaction (PCR) and quantitative PCR (qPCR). Two cases showed dubious loss of MSH2 expression, one of these with concurrent dubious loss of MSH6 on the TMA. However, MSH2 and MSH6 expression was retained on whole slide sections and PCR and qPCR analyses did not show any mutations, compatible with a microsatellite stable result. This study shows no single case with MSI in the NSND subgroup of HNSCC. Although a deficient DNA mismatch repair system is a predictive biomarker for response to immune checkpoint inhibitors, we found no evidence to support routine analysis of MSI in HNSCC, also not in the subgroup of NSND.

Prognostic stratification for microsatellite stable (MSS) gastric cancer (GC) remains challenging. This study evaluated the predictive and prognostic value of [68Ga]Ga-NOTA-GSI PET/CT imaging in a large cohort of MSS GC patients receiving chemo-immunotherapy. In this retrospective study, 145 patients with MSS GC underwent [68Ga]Ga-NOTA-GSI PET/CT after two or three cycles of chemo-immunotherapy. Measurements included SUVmax, SUVmean, GSI tumor volume (GSI-TV), total lesion uptake (TLU), tumor-liver ratio (TLR), and tumor-blood ratio (TBR). The study analyzed associations between short-term treatment response (RECIST 1.1 or tumor regression grade score) and progression-free survival (PFS) using receiver operating characteristic (ROC) curves, logistic regression, and Cox proportional hazards models. Responders exhibited significantly higher uptake of [68Ga]Ga-NOTA-GSI than non-responders, including SUVmax, sumSUVmax, and TBR (all P < 0.05) across all patients and various subgroups, while volumetric parameters (GSI-TV, TLU) showed no notable difference. SUVmax was a reliable predictor of response (AUC = 0.755 for all patients; AUC = 0.882 for the neoadjuvant subgroup). In survival analysis, an SUVmax ≥ 2.6 independently predicted significantly longer PFS (median PFS of 14.0 vs. 9.0 months; hazard ratio, 0.673; P = 0.016). The study highlighted the significant value of [68Ga]Ga-NOTA-GSI PET/CT in assessing the effectiveness of chemo-immunotherapy and predicting outcomes in MSS gastric cancer patients. Subgroup analysis confirmed its reliable predictive power across neoadjuvant, palliative, and adjuvant treatments, supporting the potential for its broad clinical application.

Lynch Syndrome (LS) is a hereditary cancer predisposition syndrome caused by germline pathogenic/likely pathogenic variants in mismatch repair (MMR) genes. While LS is not traditionally thought to increase childhood cancer risk, some studies have shown an increased prevalence of germline MMR variants in the pediatric oncology population. Herein, we discuss 55 individuals with pediatric cancer and LS. Of these, MSH2 was the most common germline change (36%). Of those tested for loss of heterozygosity (LOH) or microsatellite instability (MSI), the majority had LOH present (78%) and were MSI high (71%), suggesting the contribution of LS to oncogenesis in these individuals.

Central nervous system inflammatory myofibroblastic tumors are rare; pediatric DCTN1::ALK fusion cases are exceptionally uncommon. Here, we present an eight-year-old boy who presented with headache, vomiting, and a rapidly enlarging right frontal scalp mass. An MRI showed a dural, extra-axial lesion with mass effect. Histology confirmed IMT, and ALK immunohistochemistry was positive; next-generation sequencing (NGS) identified DCTN1 (exon 1-27)-ALK (exon 20-29) fusion, and FISH confirmed ALK rearrangement (33/100 nuclei). Genomic metrics showed tumor mutational burden (TMB) of 0.94/Mb, microsatellite stability, and CNV burden of 2.1%. He underwent near total resection followed by alectinib; to our knowledge, this is the first reported young pediatric (<10years old) CNS IMT with this fusion.

Abstract Precision oncology strategies guided by tumor molecular profiling often target key genomic aberrations in patients. Herein, we assembled National Cancer Center–Clinical Diagnostics Knowledgebase, compiling clinical targeted sequencing data from 6935 tumor tissues and matched normal samples, along with available pathological and clinical information. Comprehensive genomic profiling was conducted to characterize tumor type‐specific somatic alterations, and comparative analyses were performed across distinct cohorts. Key genomic characteristics included high‐frequency alterations in TP53 (57.8%), APC (22.6%), KRAS (21.3%), and EGFR (17.5%), among which EGFR mutations were significantly enriched in lung adenocarcinoma patients. In this cohort, 70.2% of the samples harbored at least one clinically actionable genomic aberration. 14.9% of patients showed high tumor mutational burden (TMB &gt; 10 mutations/Mb), and the TMB level was significantly higher in patients with microsatellite instability‐high than in those with microsatellite stability. We also correlated next‐generation sequencing (NGS) results with conventional molecular pathology assays. We found high consistency between ERBB2 focal amplification cases determined by NGS and clinically targetable ERBB2 amplification/HER2 overexpression cases. In conclusion, this study constructed a large‐scale real‐world genomic dataset representative of Chinese cancer patients, spanning multiple tumor types. Moreover, our findings underscore the clinical value of NGS in identifying patients with ERBB2 amplification who may potentially benefit from targeted treatments, particularly in non‐small‐cell lung cancer cases where NGS panel testing is prioritized.

Pembrolizumab plus lenvatinib in recurrent gynaecological clear cell carcinoma (LARA): a multicentre, single-arm, phase 2 trial.

Colorectal cancer (CRC) remains a major global health burden. While precision therapies like anti-PD-1 and anti-EGFR antibodies show remarkable efficacy, their application is constrained by stringent biomarker requirements, limiting patient benefit. Diverse animal models—including chemically induced, genetically engineered, and transplantation-based systems—have advanced our understanding of CRC pathogenesis but exhibit limited power in predicting therapeutic outcomes for defined patient subgroups. A central challenge is their imperfect recapitulation of key aspects of human CRC biology, specifically anatomical tumor localization, faithful representation of the tumor immune microenvironment (TME), and a frequent lack of rigorous molecular characterization. This gap underscores the urgent need for advanced models that better mirror human disease to support translational research. This review critically evaluates the establishment, advantages, and limitations of prevalent CRC models, focusing on their capacity to replicate key immunological features of human CRC, such as the complex immune landscape and response to immunotherapies. We examine how discrepancies in anatomical site, immune cell composition, and host immunity between animal models and human patients compromise predictive accuracy, particularly for evaluating immune-checkpoint inhibitors (ICIs) in microsatellite-stable (MSS) tumors. By synthesizing these critiques, we aim to provide a framework for developing immunologically relevant models to accelerate the discovery of effective, personalized immunotherapies for CRC.

Molecular tumor boards (MTBs) are essential for selecting therapies for patients with rare and advanced cancers. We hypothesized that integrating biomarkers beyond targeted DNA/RNA next-generation sequencing (NGS) could increase actionable findings. Human epidermal growth factor receptor 2 (HER2)-low status has emerged as a critical biomarker in breast cancer, with potential relevance across other tumor types. Homologous recombination deficiency (HRD) is pivotal for the application of Poly(ADP-Ribose)-Polymerase (PARP) inhibitors in ovarian and breast cancer, although its role in other malignancies remains unclear. Antibody-drug conjugates (ADCs) are expanding precision oncology, with promising biomarkers like Trop-2, Nectin-4, and folate receptor alpha (FRα) showing potential across multiple tumor entities. Tumors were analyzed using the TSO500® panel, enabling tumor mutational burden (TMB) readout. HER2 status was assessed via immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), alongside antibody-drug conjugate (ADC) IHC, microsatellite instability (MSI) polymerase chain reaction (PCR), mismatch repair (MMR) IHC, programmed death-ligand 1 (PD-L1) IHC, and HRD analysis. Cases were discussed weekly, and outcomes were systematically tracked. Data analysis evaluated the benefit of additional biomarker assessments. Among 658 patients, 329 received therapy recommendations, 182 based on supplementary biomarker analyses. One hundred recommendations were implemented, with 37% attributed to supplementary diagnostics. Among 64 response-evaluable patients, the clinical benefit rate (complete response + partial response + stable disease) was 45.3%. HER2-low status notably expanded targeted therapy options across tumor types, with similar implementation rates for HER2-low and HER2-amplified tumors. HRD analysis refined stratification in tumors with mutations in homologous recombination repair (HRR) genes beyond BRCA1/2, including PALB2, ATM, and CHEK2. ADC IHC supported 20 recommendations and two therapy implementations. The integration of additional biomarker assessments into MTB workflows enhances precision oncology by expanding the pool of patients eligible for targeted therapies.

Background/Objectives: The latest National Comprehensive Cancer Network (NCCN) Central Nervous System (CNS) Guidelines recommend utilizing next-generation sequencing (NGS) to enable comprehensive genomic profiling (CGP) as the preferred approach for molecular characterization of central nervous system (CNS) malignancies. CNS malignancies present distinct challenges due to the infeasibility of tissue-based testing for many patients and the restrictive nature of the blood–brain barrier (BBB) making plasma-based liquid biopsy an ineffective alternative. Recent advances in liquid biopsy have extended molecular testing beyond plasma to include cerebrospinal fluid (CSF), which serves as a valuable source for tumor-derived nucleic acids. Methods: The Belay Summit™ 2.0 is a high-throughput CGP assay capable of detecting multiple variant types, including single nucleotide variants (SNVs) and small insertion and deletions (Indels), copy number variations (CNVs), gene fusions, splice variants, and immunotherapy biomarkers such as microsatellite instability (MSI) and tumor mutational burden (TMB). This study details the analytical and clinical validation of Summit™ 2.0 to assess its technical performance and clinical sensitivity. Analytical validation was conducted using 68 specimens, demonstrating robust and reproducible detection of all variant types with 15 ng of CSF-derived total nucleic acid (tNA). Results: The analytical sensitivity of the Belay Summit™ 2.0 assay for SNVs and Indels was determined to be 96.7% with a 100% limit of detection (LoD) at a variant allele frequency of 0.3%. Clinical validity was evaluated across a cohort of 118 CSF specimens, including both primary and metastatic CNS tumors, demonstrating 96% sensitivity and 98% specificity. Conclusions: These findings support the use of the Belay Summit™ 2.0 assay for accurate and reproducible genomic profiling of CNS tumors using tumor-derived nucleic acids from CSF in patients for whom tissue-based testing is considered infeasible, unsafe, or not deemed by the prescribing physician to be clinically appropriate.

Lynch syndrome is the result of pathogenic variants in mismatch repair genes that increase the risk of cancer, including adrenocortical carcinoma. Little is known, however, about the clinical characteristics of patients with Lynch Syndrome-associated adrenocortical carcinoma. In order to understand the clinical characteristics and prevalence of Lynch Syndrome-associated adrenocortical carcinoma, we conducted a retrospective chart review of patients with adrenocortical carcinoma and germline genetic testing results indicating pathogenic variants in mismatch repair genes consistent with Lynch Syndrome at a single, academic, tertiary-care institution. In total, 21 patients with Lynch Syndrome-associated adrenocortical carcinoma were identified from 2003 - 2024. Three patients met Amsterdam I criteria, and 12 patients met Amsterdam II criteria (including adrenocortical carcinoma as a Lynch Syndrome-associated cancer). More than 90% of patients with available histopathology had high-grade tumors, suggesting a more aggressive nature. The prevalence of Lynch Syndrome-associated adrenocortical carcinoma is estimated at 2.6%. This study further demonstrates that adrenocortical carcinoma is a Lynch Syndrome-associated cancer and may be associated with high-grade disease. Furthermore, our findings suggest that further research should be pursued to investigate the potential utility of immunotherapy for adrenocortical carcinoma, especially in the presence of microsatellite instability.

167 Background: Retreatment with oxaliplatin-based regimens after progression to standard therapy, is a common practice in patients with metastatic colorectal cancer (mCRC), although efficacy data are limited. This study aimed to characterize mCRC patients retreated with oxaliplatin in a tertiary hospital. Methods: We reviewed 164 mCRC patients retreated with oxaliplatin from 2015 to 2021. Clinical and molecular data were analyzed. Fisher's exact test, Mann-Whitney U, log-rank test and Cox regression were used for statistical analysis. Results: Most of the patients were male (n=102, 62.2%), with a median age of 63 years. Among them, 73% (n=119) had left-sided tumors, while 35% (n=57) had rectal tumors. 91.5% underwent primary tumor resection, and 66% were diagnosed with metachronous metastatic disease. The predominant metastatic site was the liver (42%), followed by the peritoneum (30%) and lungs (26%). Furthermore, 63% of the patients had only one metastatic site. Regarding molecular profiling, 49% of the patients exhibited KRAS mutations, 11% had BRAF mutations, and 2% had microsatellite instability. Additionally, 57% of the patients underwent adjuvant therapy with oxaliplatin. The median number of lines of systemic treatment administered was four. Compared to the rest of the registry population (n=402), patients retreated with oxaliplatin were younger (63 vs 67 years, p=0.000), had more rectal tumors (34.8% vs 23.1%, p=0.019), and had primary tumors resected (91.5% vs 76.6%). They also displayed higher rates of metachronous metastatic disease (65.9% vs 35.4%, p=0.000) and lung metastases (26.2% vs 17.7%, p=0.028), with a trend towards fewer liver metastases (42.1% vs 50.7%, p=0.064). These patients often had normal CA19.9 (72.5% vs 56%, p=0.001) and LDH levels (81.3% vs 64.4%, p=0.001) at diagnosis, and received more lines of treatment (4 vs 2, p=0.000). Median progression-free survival (mPFS) for retreatment was 7.4 months. The disease control rate (DCR) was 64.5%, with an objective response rate (ORR) of 27.6%. Patients who received adjuvant oxaliplatin had numerically better mPFS (8.47 vs 5.78 months, p=0.27) and DCR (71.9% vs 51.9%, p=0.017). Retreatment beyond third line with oxaliplatin led to poorer mPFS (5.1 vs 7.9 months, p=0.24) and DCR (50% vs 67.8%, p=0.086). No differences in mPFS or DCR were identified regarding sex, age (&gt;70 vs &lt;70 years), or molecular profiling, although there was a trend for better DCR in patients without RAS/BRAF mutations (71.7% vs 59%, p=0.12). Conclusions: Retreatment with oxaliplatin seems to have a greater benefit in patients with prior adjuvant oxaliplatin therapy, treated before third line, and without RAS/BRAF mutations. Age or sex did not affect outcomes.

Background The National Comprehensive Cancer Network recommends microsatellite instability (MSI)/mismatch repair (MMR) testing to guide genetic counseling referrals for Lynch syndrome (LS) in patients with colorectal cancer. Studies show poor adherence with genetic counseling referral guidelines. Colon and rectal cancers are frequently treated as one entity despite molecular, epidemiologic, and biologic differences. Methods We investigated facility- and patient-level adherence with genetics testing/referral guidelines for LS and other germline mutations among rectal cancer patients at one institution. This is a retrospective review of patients with rectal cancer at a tertiary hospital from 2018 to 2023, excluding years 2020 to 2022 to minimize confounding factors associated with COVID-19. Indications for genetic testing/referrals were based on the Collaborative Group of the Americas on Inherited Colorectal Cancer guidelines. Results We sampled 177 patients, aged 27 to 96 years. A total of 149 (84.2%) underwent MMR/MSI testing; 47 (26.6%) were eligible for genetics referral. Nineteen (40.4%) were referred to genetics, and 14 (73.7%) underwent counseling/testing. One patient was diagnosed with LS, two with MUTYH-associated polyposis, and one with BRCA2. Conclusion This study demonstrates poor facility-level adherence with MSI/MMR testing recommendations and poor patient-level compliance with genetic referrals in rectal cancer. When recommendations were met, patients with germline mutations benefited from adjustments to their disease management.

Mismatch repair deficiency (dMMR) colorectal cancer (CRC) is characterized by abundant tumor-infiltrating lymphocytes and tertiary lymphoid structures (TLSs). However, while B cells are pivotal for TLS formation, their function and the signaling pathways driving their activation in dMMR CRCs remain undefined. Data from The Cancer Genome Atlas (TCGA) database analyzed by XCELL method and multiplex immunofluorescence (MIF) staining tissue slides were used to compare the abundance and distribution of TLSs and B cell populations between dMMR and proficient MMR cohorts. Then MLH1 knockdown models both in vitro and in vivo were used to mimic dMMR/high microsatellite instability (MSI-H) tumors and explore the influence of tumor cells on B cell behavior. TCGA analysis and MIF staining revealed a significant association between memory B cell abundance, TLS formation, and improved prognosis in dMMR CRCs. In vivo MLH1 knockdown models showed that B cell depletion enhanced tumor growth and reduced the efficacy of anti-PD-1 treatment in dMMR CRCs. Furthermore, in vitro experiments demonstrated a dsDNA/STING/type I interferon (IFN)/STAT1/ccl19 signaling pathway mediating the dMMR-induced increase in memory B cells. In conclusion, these findings show that CCL19 generated by STING/type I IFN/STAT1 pathway in dMMR/MSI-H CRC cells can promote the expansion of memory B cells, which suppresses tumor growth and enhances the efficacy of PD-1 blockade.

ObjectiveColorectal cancer (CRC) patients with high microsatellite instability (MSI-H) and mismatch repair deficiency (dMMR) had heterogeneous pathology and distinct prognoses. This study aimed to examine the difference in the gene expression profile of dMMR/MSI-H CRC patients with different disease stages and explore the different molecular mechanisms of disease progression.MethodsA total of 47 patients with dMMR/MSI-H CRC were enrolled and retrospectively studied, including 27 stage II and 20 stage IV patients. Each patient had paired tumor tissue and white blood cell samples, which were analyzed by next-generation sequencing (NGS) of 416 cancer-relevant genes. Pathway enrichment analysis was then performed to analyze the disease stage-specific signaling pathways.ResultsA total of 2878 mutation sites, spanning 378 mutated genes, were detected from the 47 dMMR/MSI-H CRC patients. The mutation frequencies of SMARCA4, EPHA3, MTHFR, RAD50, and PDGFRB were significantly higher in stage II patients than in stage IV patients (p < 0.05), whereas the stage II patients had significantly lower mutation frequencies of TSC2, FGFR1, PTPN13, SMAD3, and STK11 than stage IV patients (p < 0.05). Sixty-three mutated genes were unique to stage II tumors, while 36 mutated genes were exclusively present in stage IV tumors. Pathway analyses demonstrated the PI3K-AKT pathway was shared by both stage II and stage IV tumors, whereas multiple other signaling pathways showed disease stage-specific enrichment.ConclusionThere were profound differences in mutational profile and molecular mechanisms between stage II and stage IV dMMR/MSI-H CRC.

Comprehensive genomic profiling (CGP) is crucial in precision oncology, yet its real-world utility remains unclear. Here we analyzed data from the Japanese nationwide Center for Cancer Genomics and Advanced Therapeutics database, including clinical and genetic data from 54,185 patients with advanced solid tumors (consisting of 81 common and rare tumor types) who received CGP with a targeted sequencing panel covering 324 genes as part of their clinical care. We assessed the prognostic value of CGP-guided clinical evidence-level classification, showing that alterations predicting response to Pharmaceuticals and Medical Devices Agency-approved or Food and Drug Administration-approved therapies and to therapies supported by well-powered studies with expert consensus are detected in 16.6% and 8.1% of patients, respectively, and are associated with better prognosis than those with lower clinical evidence levels. Only 8% of patients receive CGP-guided approved-experimental genomic biomarker-linked therapies, although the proportion has improved over time. Substantial differences were observed across tumor types, with the proportions exceeding 20% in thyroid and lung cancers but remaining below 2% in pancreatic and liver cancers. Tumor-agnostic biomarker analyses reveal that tumor mutational burden (TMB) ≥20 mutations per megabase predicts better outcome across tumor types, regardless of microsatellite instability status, in TMB-high patients receiving pembrolizumab. Conversely, extramammary Paget's disease is exceptionally resistant to pembrolizumab. The large-scale nationwide database allows evaluating inter-tumor type differences and investigating evidence-scarce situations, delineating where CGP offers greater benefit. These real-world findings complement those from clinical trials and prospective sequencing projects regarding CGP, providing valuable information for individualized treatment.

Emerging evidence highlights the overexpression of Protein-L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) in multiple malignancies. However, its pan-cancer prognostic significance, tumor immune microenvironment (TIME) interactions, and therapeutic implications remain underexplored. Multi-omics data were integrated from UCSC Xena, GTEx, UALCAN, and published cohorts. PCMT1 expression patterns were systematically analyzed across 33 cancer types. Associations between PCMT1 and clinical outcomes, immune infiltration, immune checkpoint genes (ICGs), tumor mutation burden (TMB), microsatellite instability (MSI), and drug sensitivity were evaluated using bioinformatics pipelines. Our pan-cancer analysis revealed differential expression patterns of PCMT1 across various malignancies, with significant upregulation in 20 cancer types and downregulation in 3 cancer types. Notably, PCMT1 overexpression was predominantly observed in epithelial-origin tumors, such as ACC (adrenocortical carcinoma), BRCA (breast invasive carcinoma), COAD (colon adenocarcinoma), and LUAD (lung adenocarcinoma). Survival analysis demonstrated that elevated PCMT1 expression was significantly correlated with unfavorable prognosis in multiple epithelial tumors, particularly in BRCA, esophageal carcinoma (ESCA), head and neck squamous cell carcinoma (HNSC), liver hepatocellular carcinoma (LIHC), and mesothelioma (MESO). Furthermore, comprehensive analysis identified significant associations between PCMT1 expression and various tumor microenvironment features, including immune scores, six distinct immune cell types, four immunosuppressive cell populations, cancer-associated fibroblasts (CAFs)-related markers, and immunosuppressive factors. PCMT1 expression also showed significant correlations with tumor mutation burden (TMB), microsatellite instability (MSI), DNA stemness score (DNAss), and RNA stemness score (RNAss). Particularly noteworthy was the strong positive correlation between PCMT1 expression and CAFs infiltration, along with their associated factors. These findings were further validated in independent immunotherapy cohorts, where PCMT1 consistently demonstrated immunosuppressive characteristics. Multi-omics analysis suggests that PCMT1 may serve as a potential prognostic biomarker and a novel immunotherapy target for pan-cancer.