Immune checkpoint inhibitors (ICIs) are now being introduced into perioperative treatment for several solid tumors. This strategy is usually explained by tumor reduction before surgery or by the elimination of minimal residual disease (MRD) after surgery. However, these explanations may not be sufficient to understand why the timing of ICI treatment, especially before lymph node (LN) removal, is important. In this review, we discuss tumor-draining lymph nodes (tdLNs) from two different aspects. tdLNs are anatomical routes for regional and distant metastasis, but they are also sites where tumor antigens are presented and tumor-specific T cell responses are generated. In particular, tdLNs may maintain stem-like or progenitor-exhausted CD8⁺ T cells, which can respond to PD-1 blockade and give rise to more differentiated exhausted T cells in the tumor. From this viewpoint, neoadjuvant ICI may be effective because the primary tumor, antigen flow, dendritic cell migration, and tdLN-based T cell priming are preserved. We also discuss the possible role of adjuvant ICI in controlling MRD, micrometastases, and metastatic-site draining LNs, and consider future implications for LN surgery and postoperative immune surveillance.

Advanced urothelial carcinoma (aUC) has a poor prognosis, and real-time monitoring of treatment response remains clinically challenging. Circulating tumor DNA (ctDNA) has emerged as a promising non-invasive biomarker that may reflect tumor burden and molecular response. In this study, we analyzed ctDNA dynamics using a urothelial carcinoma-specific mutation panel and the non-overlapping integrated read sequencing system (NOIR-SS), a high-fidelity deep sequencing platform incorporating molecular barcoding for enhanced analytical sensitivity. Tumor tissue and serial plasma samples were collected from 15 patients with aUC treated with dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC). The custom panel targeted hotspot mutations in TP53, FGFR3, KRAS/HRAS, and the TERT promoter. Based on tumor-derived mutations, a tumor-informed approach was used to track ctDNA in plasma. ctDNA was detectable in 10 of 15 patients prior to ddMVAC and showed a trend toward association with total tumor volume, especially in cases with liver metastases. In contrast, ctDNA detection was limited in cases with only pulmonary metastases. Longitudinal changes in variant allele frequency largely mirrored treatment response, although discrepancies were observed in two cases, likely reflecting subclonal resistance. While the NOIR-SS-based assay proved sensitive and informative, limitations include the cost and time required for sequencing, potential temporal discordance between tissue and plasma sampling, and the absence of correction for clonal hematopoiesis of indeterminate potential. Overall, ctDNA profiling using this targeted panel and NOIR-SS suggested the feasibility of sensitive, non-invasive molecular monitoring in aUC, and may have future clinical applicability if validated prospectively in larger cohorts.

Adoptive cell therapy (ACT) with tumor-specific CD8+ T cells (TSTs) induces tumor regression but rarely achieves durable responses in solid tumors. This limitation stems from secondary counter-regulatory mechanisms that are also induced by ACT, notably the recruitment of tumor-infiltrating myeloid cells (TIMs). However, the precise dynamics of these responses and the optimal TST dosing strategies to overcome their immunosuppression remain largely unclear. Here, we developed a mathematical model of ACT incorporating TIM-driven counter-regulation and simulated alternative TST dosing strategies based on data from B16F10 melanoma-bearing mice. Our models revealed that, compared with a single administration strategy, fractionated and response-guided dosing strategies reduced tumor burden by up to 83% while using about 40% fewer TSTs. These results were supported by transcriptomic analysis showing that ACT-induced TIMs initially exhibited pro-inflammatory traits but later shifted into suppressive states, suggesting that fractionated TST dosing could repeatedly induce their stimulatory potential. Together, our findings advance understanding of counter-regulatory mechanisms in ACT and highlight the potential of fractionated dosing as a rational strategy to overcome them.

Objective Perioperative immune checkpoint inhibition has changed the conceptual framework of treating resectable locally advanced head and neck squamous cell carcinoma. This review aims to provide oral and maxillofacial surgeons with a practical immunological framework for interpreting perioperative immune checkpoint inhibition in oral cancer. Methods This narrative review summarizes and interprets recent clinical trials, guidelines, and translational studies relevant to perioperative pembrolizumab, PD-1 signaling, T-cell exhaustion, tumor-draining lymph nodes, tertiary lymphoid structures, pathological response, immune-related adverse events, and molecular residual disease. Results Perioperative pembrolizumab has shifted immune checkpoint inhibition from a treatment for recurrent or metastatic disease to a curative-intent strategy integrated with surgery. PD-1 signaling should be understood as a rheostat that regulates T-cell receptor and CD28 signaling rather than as a simple inhibitory brake. Durable responses to immune checkpoint inhibition are hypothesized to depend on the preservation and functional availability of the progenitor exhausted T-cell reservoir and its capacity to supply tumor-reactive progeny to the tumor microenvironment. Tumor-draining lymph nodes and tertiary lymphoid structures are therefore not only anatomical or pathological entities but also coordinated, multicellular immunological niches involving CD8-positive T-cell differentiation, CD4-positive helper subsets, B cells, and antigen-presenting cells relevant to treatment response. Surgical specimens after preoperative treatment should be interpreted as sources of pathological, spatial, immune, and molecular information. Conclusions Oral and maxillofacial surgeons should integrate tumor immunology into perioperative decision-making, specimen handling, adverse-event management, and translational research. This immune-aware framework may improve the interpretation of surgical treatment in the era of perioperative immunotherapy.

Tertiary lymphoid structures (TLS) support local antitumor immunity and are associated with favorable clinical outcomes in most cancers; however, many questions remain about how signaling and cell state changes are coordinated spatially within these structures. Using spatial transcriptomics data from TLS-containing tumors, we computationally inferred 71 cell states with EcoTyper across all major immune lineages and profiled their spatial organization with respect to the TLS-centric abundance gradient and weighted chemokine networks (CXCL13, CXCL12, and CCL19/21). Both of these strategies indicate that specific aspects of core-periphery organization only become apparent at the cell state level of resolution. Cell states of the same lineages were observed to diverge in their relationship to TLS, with some encompassing both TLS-enriched and depleted states. Of particular note, two inferred TLS-enriched CD4 T cell states had distinct marker gene programs, and CD4.T_S02 was more abundant toward the geometric TLS core. Likewise, chemokine network analysis further supported these findings and indicated two recurrent cell state communities: a lymphocyte activation one confined to TLS, and an effector-focused one that extended into the surrounding tissue, with a neutrophil cell state of tentative identity recurring as a hub across all three axes. Taken together, these results indicate that TLS are spatially zoned structures, with an active core and more diffuse effector periphery that are organized through a shared key set of chemokine signaling pathways.

While immune checkpoint inhibitors (ICIs) have failed to improve outcomes in unselected ovarian cancer populations, objective responses are observed in a minority of ovarian clear cell carcinoma (OCCC) cases, implying biological heterogeneity and a yet-undefined immunologically responsive subset within this histotype. We performed immunohistochemical profiling of tumor-infiltrating immune cells and analyzed transcriptomic data from human OCCC cohorts. Functional studies were conducted using an immunocompetent syngeneic OCCC mouse model to assess the effects of IL-17 on tumor cell inflammatory signaling, immune microenvironment remodeling, and responsiveness to immune checkpoint blockade, including single-cell RNA sequencing of tumor-infiltrating T cells. OCCC exhibited an immune-sparse tumor microenvironment with relative enrichment of CD4⁺ T cells. RORC expression was elevated in OCCC but showed intertumoral heterogeneity. In the transcriptome data (n = 180), an IL17Ahigh subset (5

Triple-negative breast cancer (TNBC) is an aggressive subtype characterized by limited targeted therapies and high recurrence rates. While immune checkpoint inhibitors (ICIs) have shown promise, their efficacy as monotherapy is limited. Clinically, ICIs demonstrate significant benefit primarily when combined with chemotherapy, particularly in the neoadjuvant setting for early-stage TNBC, which yields superior outcomes compared to adjuvant therapy. This review elucidates the tumor immunological principles underlying these observations. We discussed how the suppressive tumor microenvironment (TME), progressive T cell exhaustion, and associated epigenetic scarring constrain ICI monotherapy effectiveness. Crucially, we highlight the immunological advantages of the neoadjuvant approach: the presence of the primary tumor provides abundant antigens, and intact tumor-draining lymph nodes (TDLNs) act as critical sites for ICI-mediated priming and expansion of naïve and precursor exhausted T cells. This robust activation within TDLNs enhances systemic anti-tumor immunity and expands the T cell repertoire, a process less effectively achieved in the adjuvant setting after tumor resection. These mechanisms provide a strong rationale for the improved pathological complete response (pCR) rates and event-free survival observed with neoadjuvant chemoimmunotherapy, as demonstrated in trials like KEYNOTE-522. We further explore the implications for adjuvant therapy decisions based on treatment response, the challenges of ICI resistance, the need for predictive biomarkers, management of immune-related adverse events (irAEs), and future therapeutic directions. Understanding the dynamic interplay between chemotherapy, ICIs, T cells, and the TME, particularly the role of TDLNs in the neoadjuvant context, is essential for optimizing immunotherapy strategies and improving outcomes for patients with TNBC.

The immune landscape of tumor-draining lymph nodes (TDLNs) plays a critical role in shaping antitumor responses and influencing prognosis in oral squamous cell carcinoma (OSCC). Among patients with lymph node (LN) metastasis, clinical outcomes vary widely, yet reliable biomarkers for prognostic stratification remain limited. This study aimed to identify immune features in tumors and LNs that differentiate between favorable and poor outcomes in OSCC patients with nodal metastasis. We analyzed T cell receptor (TCR) CDR3 repertoires and the expression of immune-related genes in primary tumors and paired sentinel LNs from OSCC patients who underwent tumor resection and lymphadenectomy. Patients were divided into three groups: Group A (no nodal metastasis), Group B1 (metastasis without recurrence), and Group B2 (metastasis with recurrence). TCR diversity was assessed using the Shannon index. The expression of immune-related genes (e.g., CD3E, CD4, CD8B, FOXP3, CTLA4, IL2, IL4) was measured by quantitative PCR and normalized to GAPDH. TCR diversity was lower in tumors than in non-metastatic LNs, reflecting clonal expansion. Metastatic LNs exhibited tumor-like diversity, suggesting infiltration by tumor-reactive clones. Tumor gene expression did not differ across groups, but LNs from metastatic cases showed the reduced expression of several immune genes. Notably, CD3E, CD8B, CTLA4, IL2, and IL4 distinguished B1 from B2. The immune profiling of LNs offers superior prognostic value over tumor analysis in OSCC patients with LN metastasis. LN-based evaluation may aid in postoperative risk stratification and personalized postoperative management and could inform decisions regarding adjuvant therapy and follow-up strategies.

RNA vaccines based on lipid nanoparticles (LNPs) encapsulating in vitro transcribed mRNA (IVT-mRNA) are a successful but evolving vaccine modality. It has been increasingly recognized that LNPs, which are mainly composed of ionizable lipids, have two roles in the action of RNA vaccines: delivering mRNA into the cytoplasm by overcoming the endosomal membrane and stimulating the innate immune system as an adjuvant. In this study, we report the development of LNPs with enhanced capability to induce cellular immunity by using a combination of ionizable lipids: one containing an oleic scaffold with high transfection activity (ssPalmO-Phe; SS-OP) and the other containing a vitamin E scaffold with high adjuvant activity (ssPalmE; SS-EC), referred to as LNPOP/EC. The formulation's efficacy was evaluated in tumor-bearing mice, focusing on immune responses and tumor suppression. The results showed that the inclusion of vitamin E moieties in LNPOP/EC significantly enhanced cellular immune responses and suppressed tumor growth in an E.G7-OVA tumor-bearing mouse model. Additionally, it demonstrated robust activation of reactive CD8+ T cells specifically recognizing the neoantigens mCdt1, mScarb2, and mZfp106, which are expressed in YTN16 murine gastric cells. Suppression of YTN16 tumors was also observed using LNPOP/EC. The study suggests that LNPOP/EC is a viable platform for RNA-based cancer vaccines, offering a potent combination of gene expression and immune stimulation.