BACKGROUND:Allergic rhinitis (AR) prevalence is increasing worldwide. However, while information on the economic burden of AR remains limited globally, nationwide data for Japan are similarly scarce. Therefore, we investigated healthcare utilization and prescription drug costs for seasonal AR using a nationwide claims database, primarily focusing on spring AR. METHODS:This observational study used the National Database of Health Insurance Claims (2018-2019). Patients with spring AR were defined as those with an AR-related diagnosis and prescriptions covering ≥14 days in each of the two spring pollen seasons (January-April) in 2018 and 2019 (pre-COVID-19 years with heavy pollen dispersal). Patients with summer (May-August) and autumn (September-December) AR were similarly identified, whereas patients with perennial-only AR were excluded. We calculated the number of patients, healthcare visits, drug costs, and the correlation between the number of spring AR patients and pollen counts. RESULTS:Spring AR involved 12.9 million patients (female-to-male ratio, 1.36), with annual prescription drug costs of 101.8 billion yen (7874 yen per patient), a mean of 3.05 visits per season, and 83% of patients visiting outpatient clinics without beds. Regional patient numbers were correlated with pollen counts (Spearman's r = 0.61). Summer and autumn AR involved 5.7 million and 6.1 million patients, with costs of 38.7 and 42.4 billion yen, respectively. CONCLUSIONS:Patients with seasonal AR identified using strict criteria totaled 24.7 million annually, with drug costs totaling 182.9 billion yen. These figures represent a conservative estimate of the minimum medical expenditure for seasonal AR in Japan.

Natural killer T (NKT) cells show intense tumor-killing activity through direct and indirect pathways. However, humans have less than 0.01% of NKT cells in the peripheral blood, making it difficult to apply NKT cells for cancer treatment. We have successfully produced invariant NKT cells derived from induced pluripotent stem cells (iPSC-iNKT cells) and demonstrated the tolerability of this product in a previous phase 1 clinical trial. Although the iPSC-iNKT cells showed substantial anti-tumor activity against various tumor cell types when combined with α-Galactosylceramide-pulsed autologous dendritic cells (DC/Gal) in non-clinical experiments, the tolerability of this combination therapy for humans has not demonstrated yet. Thus, we planned this first-in-human phase 1 open-label clinical trial to demonstrate data on tolerability and safety, as well as explore the immunological changes that occur following this combination treatment. We hypothesize that the sequential induction of nasal submucosal DC/Gal injection and intra-arterial administration of the iPSC-iNKT cells is tolerable and has a favorable safety profile for cancer patients. This trial provides vital and fundamental information for next-phase clinical trials and future applications of iPSC-iNKT cells for various cancer patients (jRCTa030220741; URL: https://jrct.mhlw.go.jp/en-latest-detail/jRCTa030220741).

Inflammatory rhabdomyoblastic tumors (IRMT) are newly described entities characterized by a near-haploid karyotype. Most IRMTs exhibit indolent behavior; however, rare malignant transformation has been reported. We report a case of IRMT with malignant progression. A 67-year-old man presented with a painless mass in the left neck. Radiology revealed a 40-mm tumor in the left sternocleidomastoid muscle, with no evidence of distant metastasis. Core needle biopsy showed densely proliferating polygonal cells with pleomorphic nuclei, necrosis, and atypical mitoses. Based on histology, a preliminary diagnosis of pleomorphic rhabdomyosarcomas was made, although the clinical behavior seemed atypical. Nanopore DNA sequencing was subsequently performed and, within days, revealed characteristic molecular features, including relative gains of chromosomes 5, 7, and 22, a TP53 mutation, and DNA methylation profiling consistent with IRMT with malignant progression. The tumor was surgically resected, and pathological examination of the resected specimen confirmed a minor conventional IRMT component. Furthermore, infiltration of CD163-positive histiocytes was prominent, and fluorescence in situ hybridization analysis revealed two red signals (COL1A1 on chromosome 17) and four green signals (PDGFB on chromosome 22) in most tumor cells. Collectively, these histopathological, immunohistochemical, cytogenetic, and epigenetic findings established a final diagnosis of IRMT with malignant progression. Given the small tumor size, chemotherapy and radiotherapy were not administered. Nevertheless, the long-term behavior of IRMT with malignant progression remains unclear; thus, careful follow-up is warranted.

PURPOSE:Salivary gland carcinoma (SGC), particularly salivary duct carcinoma (SDC), is a rare and aggressive malignancy with no standard systemic treatment. Androgen receptor (AR) expression is frequently detected in SDC, which suggests inhibition of the AR pathway as a therapeutic strategy. We conducted a prospective phase II trial of the efficacy and safety of darolutamide, a second-generation AR signaling inhibitor, as monotherapy or in combination with goserelin, in patients with AR-positive unresectable locally advanced (LA) or recurrent/metastatic (R/M) SGC. METHODS:DISCOVARY was a multicenter, single-arm, phase II trial conducted in Japan. Patients with unresectable LA or R/M AR-positive SGC were enrolled into two sequential cohorts, a monotherapy cohort (darolutamide 600 mg orally twice daily) and a combination cohort (darolutamide plus goserelin 3.6 mg subcutaneously once every 28 days). The primary end point was objective response rate (ORR). Secondary end points included progression-free survival (PFS), overall survival (OS), safety, and health-related quality of life. RESULTS:Fifty-seven patients were enrolled (monotherapy, n = 24; combination, n = 33). In the monotherapy cohort, the confirmed ORR was 8.3% (90% CI, 1.5 to 24.0) and the median PFS was 5.7 months. In the combination cohort, ORR was 45.2% (90% CI, 29.7 to 61.3) and the median PFS was 13.1 months. Twelve-month OS rates were 91.3% and 87.0%, respectively. Most adverse events were grade 1 or 2 in severity, with no treatment-related deaths. Quality of life was preserved. No clear association between AR expression level or Ki-67 index and treatment response was evident in exploratory analysis. CONCLUSION:Darolutamide demonstrated antitumor activity in AR-positive SGC, with numerically more favorable outcomes with goserelin. Darolutamide plus goserelin may represent a chemotherapy-sparing option in this rare malignancy.

Influence of CD106 on various surface molecules

Summary of the antibodies used in flow cytometry analyses

Frequencies of exhausted CD8+ T cell cluster

Purpose Tumor-infiltrating lymphocyte (TIL) therapy has attracted increasing attention as a promising next-generation cancer immunotherapy that may overcome some limitations of current immune checkpoint inhibitors. However, the phenotypic characteristics and tumor reactivity of TILs derived from Japanese melanoma tissues remain insufficiently investigated. This study aimed to evaluate the feasibility of expanding TILs from Japanese melanoma specimens and to characterize their phenotype and autologous tumor reactivity.Methods TILs were expanded from 26 Japanese melanoma specimens, including tumors derived from primary and mucosal lesions. The phenotypes of cultured TILs were assessed, and reactivity against autologous tumor cells was evaluated in 9 available TIL samples.Results TILs were successfully expanded from Japanese melanoma tissues, consistent with previous reports from the United States. The phenotypes of cultured TILs varied substantially among cases. Among the 9 TIL samples tested for reactivity against autologous tumor cells, MHC class I-restricted specific reactivity was detected in 7 samples, including 1 sample derived from mucosal melanoma. No clear association was observed between autologous tumor reactivity and the proportion of CD3+CD8+ T cells or the expression of specific markers on CD3+CD8+ T cells.Conclusion This study is the first to characterize cultured TILs established from a series of Japanese melanoma patients. These findings suggest that the expansion of tumor-reactive TILs from Japanese melanoma tissues is feasible and may provide a basis for the development of TIL therapy in Japan.

BACKGROUND:Optimal treatment for non-metastatic unresectable salivary duct carcinoma (SDC) remains unclear. We compared outcomes of upfront biomarker-targeted systemic therapy and radiotherapy. METHODS:We retrospectively analyzed the Joint SDC Study Group registry. Thirty-one patients with centrally confirmed non-metastatic unresectable SDC were classified by initial treatment (radiotherapy or systemic therapy). Systemic therapy included trastuzumab plus docetaxel, combined androgen blockade, or chemotherapy. Progression-free survival (PFS) and overall survival (OS) were analyzed. RESULTS:Systemic therapy showed better PFS than radiotherapy (3-year PFS 47.6% vs. 30.0%, p = 0.031) without OS difference. Trastuzumab plus docetaxel showed the highest response rate (75%) and enabled curative-intent treatment in all cases, with the best PFS (3-year 87.5%, p = 0.012). CONCLUSIONS:Given the retrospective design and limited sample size, these findings should be regarded as hypothesis-generating. An upfront trastuzumab-based therapy followed by curative-intent treatment may be a promising option for selected patients with HER2-positive unresectable SDC.

Abstract Background and Objectives: The normal endometrium undergoes cyclical regeneration and frequently contains somatic mutations, yet the earliest steps of endometrioid endometrial carcinoma (EEC) development remain poorly defined. Although tumor heterogeneity arises from both genomic evolution and diversity in epithelial cell states, how these two axes interact during early tumorigenesis is not well understood. To address this question, we focused on early-stage EEC and performed an integrative analysis linking clonal architecture with cell-state heterogeneity. Methods: We performed multi-region whole-exome sequencing (WES) of uterine samples from 37 patients with early-stage EEC to map the anatomical distribution of tumor clones. Representative cases covering POLE-mutated, microsatellite instability-high, and copy-number-low subtypes underwent single-cell RNA sequencing to characterize epithelial differentiation states and reconstruct lineage relationships. Somatic mutations identified by WES were used to infer clonal structures at single-cell resolution. Patient-derived organoids were established to functionally evaluate distinct progenitor-like tumor populations. Results: Single-cell RNA sequencing revealed a spectrum of epithelial differentiation, ranging from mature ciliated and secretory cells to undifferentiated progenitor-like tumor cells. The proportions of these states varied widely not only between patients but also across regions within the same uterus. By integrating WES-derived mutations with single-cell profiles, we showed that individual tumor clones contained both progenitor-like and differentiated cells, recapitulating a hierarchical epithelial organization reminiscent of the normal endometrium. Subclonal populations differed markedly in epithelial composition and proliferative activity, indicating that clone-specific genomic alterations influence cell-state output. Notably, we identified two transcriptionally and functionally distinct progenitor-like tumor cell types, suggesting multiple differentiation routes in early tumor evolution. Conclusions: Early-stage EEC exhibits coordinated heterogeneity at genetic and cellular levels. The discovery of two progenitor-like tumor populations provides evidence for parallel differentiation programs that drive early tumor diversification. By integrating clonal evolution driven by genetic alterations with single-cell phenotypes, this study refines current EEC classification frameworks such as ProMisE and offers new biological insights into the origins, propagation, and therapeutic vulnerabilities of early-stage endometrial cancer. Citation Format: Suguru Miyata, Hiroshi Yoshida, Toyoyuki Hanazawa, Masahito Kawazu. Integrated clonal and single-cell analyses uncover progenitor-driven tumor diversification in early-stage endometrioid endometrial carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7513.

Abstract Introduction: Extrachromosomal DNA (ecDNA) contributes to oncogene amplification in human cancers, yet the mechanisms underlying the formation and function of human-viral hybrid ecDNA (hybrid ecDNA), circular elements harboring both HPV and human sequences, remain unclear. We recently identified hybrid ecDNA in human papillomavirus-associated oropharyngeal cancer (HPVOPC), a rapidly increasing malignancy. Here, we show that de novo enhancer formation at viral-human junctions activates viral oncogenes and promotes hybrid ecDNA self-amplification, revealing a tractable therapeutic vulnerability. Methods: Hybrid ecDNA was identified in HPVOPC cell lines and patient-derived xenografts (PDX) using whole-genome sequencing and AmpliconArchitect. Validation was performed by multicolor FISH. Chromatin accessibility and enhancer activity were profiled by ATAC-seq and H3K27ac ChIP-seq. Hi-C sequencing was used to assess 3D chromatin interactions and potential contacts among distinct ecDNA species. Functional significance was evaluated by CRISPR interference (CRISPRi) targeting ecDNA-derived enhancers. Therapeutic relevance was assessed by BET inhibition in vitro and in vivo. Results: Hybrid ecDNA was detected in both cell lines and PDX tumors and validated by overlapping human and HPV FISH signals. Epigenomic profiling revealed de novo active enhancers flanking HPV sequences exclusively in hybrid ecDNA(+) tumors. Hi-C demonstrated enhancer-promoter loops linking host enhancers to HPV oncogenes. CRISPRi targeting these enhancers significantly inhibited proliferation in hybrid ecDNA(+) models only (P = 0.006). BET inhibition selectively suppressed hybrid ecDNA(+) tumor growth in vivo (P = 2×10-5). Importantly, Hi-C contacts also indicated enriched interaction patterns among distinct ecDNA species, suggesting potential extrachromosomal cooperation that enhances viral oncogene expression. Conclusions: Hybrid ecDNA is a functionally critical structure in HPVOPC by generating de novo enhancers and reorganizing chromatin interactions to activate viral oncogenes, creating a therapeutic vulnerability. Contact enrichment among distinct ecDNA species further suggests participation in a broader extrachromosomal regulatory network in HPV-driven malignancies. Citation Format: Takuya Nakagawa, Jens Luebeck, Kaiyuan Zhu, Sasik Roman, Brin Rosenthal, Kathleen Fisch, Toyoyuki Hanazawa, Atsushi Kaneda, Paul S. Mischel, Vineet Bafna, Joseph A. Califano. De novo enhancer formation at human-viral junctions drives hybrid extrachromosomal DNA amplification in HPV-associated cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1925.

Additional CD106 expression data in PBMCs

Patient characteristics for prognostic analyses

Although human papillomavirus-positive (HPV(+)) head and neck squamous cell carcinoma (HNSCC), particularly oropharyngeal squamous cell carcinoma (OPSCC), is generally associated with favorable outcomes, a subset of HPV(+) OPSCC remains resistant to chemoradiotherapy. We previously stratified clinical OPSCC cases using DNA methylome profiling and identified a significant correlation between elevated DNA methylation levels and favorable treatment response. To elucidate the molecular basis of this correlation, we performed integrated methylome analyses of 64 HPV(+) HNSCC cases in The Cancer Genome Atlas (TCGA) and 29 HPV(+) OPSCC cases in our Chiba cohort. We identified 595 genes showing significantly higher DNA methylation in good responders in each cohort. Additionally, using HNSCC cell lines, we extracted genes that exhibited both high DNA methylation and decreased expression in cisplatin (CDDP) sensitive cells. Twelve genes were consistently hypermethylated across both clinical cohorts, among which two genes, ROBO1 and SULT4A1, showed statistical significance and effect size. Functional validation demonstrated that ROBO1 knockdown in unmethylated HNSCC cells significantly suppressed cellular growth (p < 0.05), and additional exposure to CDDP further synergistically reduced cellular growth (p < 0.05). Conversely, ROBO1 overexpression conferred resistance to CDDP. CDDP resistance in unmethylated HNSCC cells led to upregulation of ROBO1 expression, suggesting an inverse relationship between ROBO1 silencing and drug resistance. Mechanistically, ROBO1 suppression increased DNA damage and apoptosis following CDDP treatment. These indicate that DNA hypermethylation of ROBO1 causally correlates with better treatment response of HPV(+) HNSCC, and its chemosensitivity might be enhanced by silencing of methylation target genes.