Lymph node metastases can invade local blood vessels, exit the node, and colonize distant organs in mice

Risk of Residual Axillary Lymph Node Macrometastasis in Early Breast Cancer PATIENTS with One Positive Macrometastasis Sentinel Lymph Node

Objective

To investigate the risk factors for residual axillary lymph node macro-metastasis in early-stage breast cancer patients with a single macrometastasis sentinel lymph node (SLN).

Methods

We retrospectively analyzed the clinical data of 119 breast cancer patients diagnosed between January 2018 and September 2023, each with one positive SLN stained with methylene blue, who subsequently underwent axillary lymph node dissection. The patients were divided into two groups based on the total number of SLNs identified: fewer than three and more than three. Fisher's exact test was used for statistical analysis between groups.

Results

Among the 119 patients evaluated, 30 patients had a total of 2 sentinel lymph nodes, with 15 testing positive for residual axillary lymph nodes, yielding a positivity rate of 50.0%. Another 30 patients had 3 sentinel lymph nodes, with a positivity rate of 33.3%. An additional 32 patients each had 4 sentinel lymph nodes, with a positivity rate of 3.13%. Finally, 27 patients had 5 sentinel lymph nodes, with a 0% positivity rate. The positivity rate of axillary lymph nodes was significantly higher in the group with ≤ 3 sentinel lymph nodes (less SLN group) compared to the group with > 4 sentinel lymph nodes (more SLN group). Binary logistic regression analysis confirmed that the number of SLNs was the only significant predictor of residual lymph node macrometastasis.

Conclusion

The number of sentinel lymph nodes (SLNs) is a key factor influencing the risk of residual axillary lymph node macrometastasis in early-stage breast cancer patients with one positive SLN. Identifying a higher number of SLNs (≥4) significantly lowers the risk of residual metastasis, supporting the use of thorough SLN mapping in these cases to improve patient outcomes.

Snord67 promotes breast cancer metastasis by guiding U6 modification and modulating the splicing landscape

Previously considered "housekeeping" genes, small nucleolar RNAs (snoRNAs) are increasingly understood to have wide-ranging functions in cancer, yet their role in metastasis has been less well studied. Here, we identify the snoRNA Snord67 as a regulator of lymph node (LN) metastasis in breast cancer. Snord67 expression is enriched in LN metastases in an immune-competent mouse model of female breast cancer. In an orthotopic breast cancer model, loss of Snord67 decreases LN metastasis. In a model of lymphatic metastasis, Snord67 loss decreases LN tumor growth and distant metastases. In breast cancer cell lines, Snord67 knockout results in loss of targeted 2'-O-methylation on U6 small nuclear RNA, as well as widespread changes in splicing. Together, these results demonstrate that Snord67 regulates splicing and promotes the growth of LN metastases and subsequent spread to distant metastases. SnoRNA-guided modifications of the spliceosome and regulation of splicing may represent a potentially targetable pathway in cancer.

Targeting vascular endothelial growth receptor-2 (VEGFR-2): structural biology, functional insights, and therapeutic resistance

Angiogenesis, the process of new blood vessel formation, is a fundamental physiological process implicated in several pathological disorders. The vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are crucial for angiogenesis and vasculogenesis. Among them, the tyrosine kinase receptor VEGFR-2 is primarily expressed in endothelial cells (ECs). These cells regulate various physiological responses, including differentiation, cell proliferation, migration, and survival, by binding to VEGF mitogens. Vascular Endothelial Growth Factor Receptor 2 (VEGFR-2) is a key regulator of this process, making it a prime target for therapeutic intervention. Several drugs targeting VEGFR-2 have been approved and are currently utilized to halt the pathological axis of VEGF-VEGFR. This review will focus on the recent developments in the molecular structure and function of VEGFR-2, the molecular mechanism of VEGFR-2 activation, and its downstream signaling pathway. It will also discuss therapies and experimental drugs approved to inhibit the function of VEGFR-2 and the resistance mechanism.

Monoclonal antibodies as adjuvant therapies for resected melanoma

INTRODUCTION

Systemic adjuvant therapy is indicated in patients with high-risk, resected melanoma to reduce recurrence risk and potentially improve survival rates. Monoclonal antibodies (mAbs) target immune checkpoints and have made significant advances as systemic adjuvant therapies.

AREAS COVERED

This review discusses the main clinical trials that tested adjuvant mAbs in resected high-risk melanoma, including anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4) and anti-programmed cell death-1 (PD-1); in addition to newer immunotherapies being tested in the adjuvant setting, including anti-lymphocyte activation gene 3 (LAG-3). We also briefly discuss targeted therapies as an alternative choice. Moreover, we highlight the pros and cons of using mAbs in the adjuvant setting, the reported adverse events (AEs), and the quality of life impact. Finally, we report data related to biomarker studies tested in the context of these clinical trials.

EXPERT OPINION

Immune checkpoint inhibitors (ICIs) have been shown to significantly improve relapse-free survival (RFS) as adjuvant therapy for high-risk melanoma. The long-term impact on overall survival (OS) was demonstrated in two trials that tested ipilimumab as compared to placebo (EORTC18071) and interferon-α (ECOG-ACRIN E1609). Furthermore, emerging data with neoadjuvant therapy followed by surgery and adjuvant therapy utilizing ICIs have demonstrated improved outcomes in the management of locoregionally advanced disease when compared to upfront surgery followed by adjuvant therapy alone.

Multiple data sets to explore the key molecules and mechanism of lymph node metastasis in gastric cancer

OBJECTIVE

To explore the key molecules and regulatory mechanisms of lymph node metastasis in gastric cancer.

METHODS

The differential genes and key genes of lymph node metastasis in gastric cancer were analyzed by utilizing multiple data sets. The key genes were analyzed by GSEA analysis, transcription factor analysis, nomogram prediction model construction, immune infiltration analysis, GSVA analysis, drug sensitive analysis and single cell data analysis.

RESULTS

Abnormal expression of key genes including CDRT15P1, DENND3, F2R, FNDC3B, IRAK3, MS4A2, PDK4, PKIA and activation of related signaling pathways might be the result of ultraviolet radiation-induced DNA damage, which was closely related to lymph node metastasis in gastric cancer. The key genes were regulated by a variety of transcription factors, which were strongly connected with the invasion of immune cells and the sensitivity of a variety of drugs. The nomogram prediction model, which is based on the key genes associated with lymph node metastasis and the TNM of gastric cancer, demonstrated a high level of predictive efficiency.

CONCLUSION

CDRT15P1, DENND3, F2R, FNDC3B, IRAK3, MS4A2, PDK4 and PKIA may be the key genes affecting lymph node metastasis in gastric cancer, and F2R has higher biological importance.

Immune microenvironment of tumor-draining lymph nodes: insights for immunotherapy

Tumor-draining lymph nodes (TDLNs) play a crucial role in modulating tumor immune responses and influencing the efficacy of immunotherapy. However, our current understanding of the microenvironment within these lymph nodes remains limited. Tumors not only impair the anti-tumor activity of CD8+ T cells by creating an immunosuppressive microenvironment, but they also facilitate immune evasion and promote metastasis by altering the structure and function of TDLNs. Research has shown that tumor-specific memory CD8+ T cells (TTSM) within TDLNs are essential for the efficacy of immune checkpoint inhibitors, such as PD-1/PD-L1 blockers. Moreover, the abnormal structure of TDLNs, along with the presence of immunosuppressive cells-such as regulatory T cells (Tregs), regulatory B cells (Bregs), and immunosuppressive dendritic cells (DCs)-contributes to tumor-mediated immune evasion. Therefore, gaining a deeper understanding of the immune microenvironment within TDLNs is essential for improving the effectiveness of immunotherapies and developing novel therapeutic strategies. This review explores various TDLN-based therapeutic strategies, addressing the controversies surrounding lymph node dissection, the use of TDLNs as a source of tumor-infiltrating lymphocytes (TILs) for therapy, targeting immunosuppressive cells within TDLNs, and methods to reverse the structural abnormalities of TDLNs. These strategies offer valuable insights and potential directions for advancing tumor immunotherapy.

Altered immune signatures in breast cancer lymph nodes with metastases revealed by spatial proteome analyses

BACKGROUND

Metastasis to lymph nodes is strongly associated with reduced survival in breast cancer patients. To increase the understanding on how lymph node metastasis impairs the local immune response in affected lymph nodes, we here studied spatial proteomic changes of critical lymph node immune populations in uninvolved lymph nodes (UnLN) and paired lymph nodes with metastases (LNM) from five breast cancer patients.

METHODS

The proteome was analyzed for cortical lymphocyte compartments, subcapsular sinus (SCS) and medullary sinus (MS) CD169+ macrophages, using the Digital Spatial Profiling (DSP) platform from NanoString.

RESULTS

Our results identified a stable proteome of SCS CD169+ macrophages in LNM, with the exception for downregulation of the anti-apoptotic protein Bcl-xL and FAPα, but a clear reduction in numbers of SCS CD169+ macrophages in LNM. In contrast, the proteome of MS CD169+ macrophages, B-cell compartments and interfollicular T-cells showed altered immune signatures in LNM, indicating that the decline in SCS CD169+ macrophages coincide with a malfunction in the local, anti-tumor immune responses.

CONCLUSIONS

The findings from our study support the notion that metastasis to lymph nodes in breast cancer patients modifies local immune responses. These changes may contribute to explain unsuccessful therapeutic responses, and thereby worsened prognosis, for breast cancer patients with LNM.

Premetastatic niche mechanics and organotropism in breast cancer

Numerous physical and mechanical changes occur in the premetastatic niche. Here, we review the mechanics of the premetastatic niche and how the altered extracellular matrix and cancer cell mechanics may play a role in organotropism in breast cancer. Future research into premetastatic niche development and organotropic cell behavior should address physical alterations and biomechanical effects to the same rigor that biochemical alterations are studied.

A Highly Sensitive Tissue-specific qRT-PCR-based Assay for Detection of Melanoma Cells in Tumor-Draining Lymph Nodes

Melanoma invasion of regional lymph nodes, a critical event in the progression of this disease, is well documented as a poor prognostic factor for patients with melanoma. Assessing lymph node involvement is therefore a routine part of the diagnostic workup for patients presenting with melanoma at a T stage of ≥T2a. In clinical settings, the status and degree of melanoma lymph node involvement is traditionally characterized by histopathological analysis of tissue obtained during a sentinel lymph node biopsy, a labor-intensive and costly approach that requires technically challenging sample preparation and interpretation by a trained pathologist. Alternative approaches that might reduce the financial burden and turnaround time of a sentinel lymph node biopsy workup are therefore desirable. Likewise, the ability to accurately assess lymph node invasion by melanoma in experimental settings is necessary to gain new insights into mechanisms of distant metastasis and tumor-associated immune suppression. With these applications in mind, we recently developed, and describe herein, a tissue-specific qRT-PCR-based protocol for detecting melanoma cells within tumor-draining lymph nodes. Using murine models of lymph-node-invasive and lymph-node-noninvasive melanoma cell lines and a melanin-biosynthesis-pathway-specific Trp2 gene expression assay, we validated this method as a highly sensitive strategy for assessing lymph node involvement by melanoma. © 2025 Wiley Periodicals LLC. Basic Protocol 1: Growth and maintenance of murine melanoma cell cultures Basic Protocol 2: Extraction and quantification of RNA from murine melanoma cultures Basic Protocol 3: cDNA synthesis via reverse transcription Basic Protocol 4: Probe and primer design for TaqMan-based qPCR Basic Protocol 5: qPCR analysis of tissue-specific Trp2 gene expression Basic Protocol 6: In vitro validation of qRT-PCR Trp2 gene expression assay for detection of melanoma cells in murine whole lymph node preparations Basic Protocol 7: In vivo validation of qRT-PCR Trp2 gene expression assay for detection of melanoma cells in murine tumor-draining lymph nodes.

Lymphatic collection and cell isolation from mouse models for multiomic profiling

Premetastatic cancer cells often spread from the primary lesion through the lymphatic vasculature and, clinically, the presence or absence of lymph node metastases impacts treatment decisions. However, little is known about cancer progression via the lymphatic system or of the effect that the lymphatic environment has on cancer progression. This is due, in part, to the technical challenge of studying lymphatic vessels and collecting lymph fluid. Here we provide a step-by-step procedure to collect both lymph and tumor-draining lymph in mouse models of cancer metastasis. This protocol has been adapted from established methods of lymph collection and was developed specifically for the collection of lymph from tumors. The approach involves the use of mice bearing melanoma or breast cancer orthotopic tumors. After euthanasia, the cisterna chyli and the tumor are exposed and viewed using a stereo microscope. Then, a glass cannula connected to a 1 mL syringe is inserted directly into the cisterna chyli or the tumor-draining lymphatics for collection of pure lymph. These lymph samples can be used to analyze the lymph-derived cancer cells using highly sensitive multiomics approaches to investigate the impact of the lymph environment during cancer metastasis. The procedure requires 2 h per mouse to complete and is suitable for users with minimal expertise in small animal handling and use of microsurgical tools under a stereo microscope.

EGFR-mediated local invasiveness and response to Cetuximab in head and neck cancer

BACKGROUND

Recurrent/metastatic head and neck squamous cell carcinoma (R/M-HNSCC) is a severe, frequently lethal condition. Oncogene addiction to epidermal growth factor receptor (EGFR) is a hallmark of HNSCC, but the clinical efficacy of EGFR-targeted therapies remains low. Understanding molecular networks governing EGFR-driven progression is paramount to the exploration of (co)-treatment targets and predictive markers.

METHODS

We performed function-based mapping of differentially expressed genes in EGFR-mediated local invasion (fDEGs) using photoconvertible tracers and RNA-sequencing (RNA-seq) in a cellular 3D-model.

RESULTS

Upon alignment with public single-cell RNA-seq (scRNA-seq) datasets and HNSCC-specific regulons, a gene regulatory network of local invasion (invGRN) was inferred from gene expression data, which was overrepresented in budding tumors. InvGRN comprises the central hubs inhibin subunit beta alpha (INHBA) and snail family transcriptional repressor 2 (SNAI2), and druggable fDEGs integrin subunit beta 4 (ITGB4), laminin 5 (LAMB3/LAMC2), and sphingosine kinase 1 (SPHK1). Blockade of INHBA repressed local invasion and was reverted by activin A, laminin 5, and sphingosine-1-phosphate, demonstrating a functional interconnectivity of the invGRN. Epithelial-to-mesenchymal transition (EMT) of malignant cells and the invGRN are induced by newly defined EGFR-activity subtypes with prognostic value that are promoted by amphiregulin (AREG) and epiregulin (EREG). Importantly, co-inhibition of SPHK1 showed synthetic effects on Cetuximab-mediated invasion blockade and high expression of selected fDEGs was associated with response to Cetuximab in patient-derived xenotransplantation (PDX) and R/M-HNSCC patients.

CONCLUSIONS

We describe an actionable network of EGFR-mediated local invasion and define druggable effectors with predictive potential regarding the response of R/M-HNSCC to Cetuximab.

Ex Vivo Model of Breast Cancer Cell Invasion in Live Lymph Node Tissue

Lymph nodes (LNs) are common sites of metastatic invasion in breast cancer, often preceding spread to distant organs and serving as key indicators of clinical disease progression. However, the mechanisms of cancer cell invasion into LNs are not well understood. Existing in vivo models struggle to isolate the specific impacts of the tumor-draining lymph node (TDLN) milieu on cancer cell invasion due to the coevolving relationship between TDLNs and the upstream tumor. To address these limitations, we used live ex vivo LN tissue slices with intact chemotactic function to model cancer cell spread within a spatially organized microenvironment. After showing that BRPKp110 breast cancer cells were chemoattracted to factors secreted by naïve LN tissue in a 3D migration assay, we demonstrated that ex vivo LN slices could support cancer cell seeding, invasion, and spread. This novel approach revealed dynamic, preferential cancer cell invasion within specific anatomical regions of LNs, particularly the subcapsular sinus (SCS) and cortex, as well as chemokine-rich domains of immobilized CXCL13 and CCL1. While CXCR5 was necessary for a portion of BRPKp110 invasion into naïve LNs, disruption of CXCR5/CXCL13 signaling alone was insufficient to prevent invasion toward CXCL13-rich domains. Finally, we extended this system to premetastatic TDLNs, where the ex vivo model predicted a lower invasion of cancer cells that was not due to diminished chemokine secretion. In summary, this innovative ex vivo model of cancer cell spread in live LN slices provides a platform to investigate cancer invasion within the intricate tissue microenvironment, supporting time-course analysis and parallel read-outs. We anticipate that this system will enable further research into cancer-immune interactions and allow for isolation of specific factors that make TDLNs resistant to cancer cell invasion, which is challenging to dissect in vivo.

Lymphatic system is the mainstream for breast cancer dissemination and metastasis revealed by single-cell lineage tracing

Cancer metastasis is the primary cause of cancer-related death, yet the forces that drive cancer cells through various steps and different routes to distinct target organs/tissues remain elusive. In this study, we applied a barcoding system based single-cell lineage tracing approach to study the metastasis rate and route of breast cancer cells and their interactions with the tumor microenvironment (TME) during metastasis. The results indicate that only a small fraction of cells, accounting for fewer than 3% of total barcodes, can intravasate from the primary site into the blood circulation, whereas more cells disseminate through the lymphatic system to different organs. Tumor cells derived from the same progenitor cell exhibit different gene expression patterns in different soils, and the cancer cell-TME communication paradigm varies significantly between primary and metastatic tumors. Furthermore, metastable cells require a prewired particular cytokine expression ability which may be specific for lymph metastasis route although the underlying mechanism requires further investigation. In summary, leveraging a single-cell lineage tracing system, we demonstrate that the crosstalk between tumor cells and the TME is the driving force controlling the preferential metastatic fate of cancer cells through the lymphatic system.

Molecular Underpinnings of Brain Metastases

Brain metastases are the most commonly diagnosed type of central nervous system tumor, yet the mechanisms of their occurrence are still widely unknown. Lung cancer, breast cancer, and melanoma are the most common etiologies, but renal and colorectal cancers have also been described as metastasizing to the brain. Regardless of their origin, there are common mechanisms for progression to all types of brain metastases, such as the creation of a suitable tumor microenvironment in the brain, priming of tumor cells, adaptations to survive spreading in lymphatic and blood vessels, and development of mechanisms to penetrate the blood-brain barrier. However, there are complex genetic and molecular interactions that are specific to every type of primary tumor, making the understanding of the metastatic progression of tumors to the brain a challenging field of study. In this review, we aim to summarize current knowledge on the pathophysiology of brain metastases, from specific genetic characteristics of commonly metastatic tumors to the molecular and cellular mechanisms involved in progression to the central nervous system. We also briefly discuss current challenges in targeted therapies for brain metastases and how there is still a gap in knowledge that needs to be overcome to improve patient outcomes.

Axillary surgery versus no-axillary staging in T1N0 breast cancer: 20-year follow-up of the INT 09/98 randomized clinical trial

BACKGROUND

The role of axillary surgery in breast cancer has shifted over time from a therapeutic operation to a staging method for subsequent adjuvant therapies, through the introduction of sentinel lymph node biopsy. The discovery of molecular subtypes has since questioned the necessity of axillary staging in breast cancer.

METHODS

The INT09/98 randomized trial explored the omission of axillary surgery in early-stage breast cancer in patients under 65 years of age. From June 1998 to June 2003, a total of 565 T1N0 breast cancer patients were enrolled. The trial tested the non-inferiority of quadrantectomy without axillary surgery (QU) compared to quadrantectomy with axillary dissection (QUAD). The primary endpoint was overall survival (OS). Secondary endpoints included disease-free survival (DFS) and incidence/timing of axillary lymph node metastasis in the QU arm.

RESULTS

Follow-up at 20 years showed no significant differences between the QU versus the QUAD arm. The adjusted hazard ratio for OS was 1.18 (P = 0.326) and DFS was 1.27 (P = 0.280) respectively, both within the predetermined non-inferiority limit. Axillary relapse rates in the QU arm remained low, indicating that only a subset of metastatic nodes cause recurrences if not removed. In the QU arm, patients with favourable biological features but unknown axillary node involvement did not receive adjuvant chemotherapy, without significant differences in outcomes. The axillary relapse rate with distant metastases was similar in both arms and may reflect aggressive biology of the primary tumour.

CONCLUSION

Avoiding axillary surgery and reducing adjuvant treatments in early breast cancer does not increase distant metastases or affect long-term survival. Axillary relapsed patients with distant metastases in both QU and QUAD arms may represent cancers with genomically determined poorer prognosis, independent of surgical intervention and adjuvant therapies.

REGISTRATION NUMBER

NCT01508546 (http://www.clinicaltrials.gov).

Lymphatic transport in anti-tumor immunity and metastasis

Although lymphatic vessels (LVs) are present in many tumors, their importance in cancer has long been underestimated. In contrast to the well-studied tumor-associated blood vessels, LVs were previously considered to function as passive conduits for tumor metastasis. However, emerging evidence over the last two decades has shed light on their critical role in locally shaping the tumor microenvironment (TME). Here we review the involvement of LVs in tumor progression, metastasis, and modulation of anti-tumor immune response.

Construction and evaluation of liposomal drug delivery system for an ALK/HDACs dual-targeted inhibitor with sustained release and enhanced antitumor effect

ALK/HDACs dual target inhibitor (PT-54) was a 2,4-pyrimidinediamine derivative synthesized based on the pharmacophore merged strategy that inhibits both anaplastic lymphoma kinase (ALK) and histone deacetylases (HDACs), which has demonstrated significant efficacy in treating multiple cancers. However, its poor solubility in water limited its clinical application. In this study, we prepared PT-54 liposomes (PT-54-LPs) by the membrane hydration method to overcome this defect. The encapsulation efficiency (EE) and particle size were used as evaluation indicators to explore the preparation conditions of PT-54-LPs. The morphology, particle size, EE, drug loading content (DLC), drug release properties, and stability of PT-54-LPs were further investigated. In vitro drug release studies showed that PT-54-LPs exhibited significant slow-release properties compared with free PT-54. PT-54-LPs also showed better tumor inhibitory effects than free PT-54 without significant adverse effects. These results suggested that PT-54-LPs displayed sustained drug release and significantly improved the tumor selectivity of PT-54. Thus, PT-54-LPs showed significant promise in enhancing anticancer efficiency.

AXL promotes lymphangiogenesis by amplifying VEGF-C-mediated AKT pathway

Lymphangiogenesis has gained considerable interest due to its established role in cancer progression and dissemination of metastatic cells through lymph nodes. Deciphering the molecular mechanisms that govern lymphangiogenesis within lymph nodes holds promise for revealing novel targetable molecules and pathways to inhibit metastasis. In this study, we revealed a previously unrecognized role of AXL, a tyrosine kinase receptor, in the lymphatic vessel formation. We first validated the expression of AXL in lymphatic endothelial cells (LECs), followed by functional studies using RNA interference and pharmacological inhibition with R428/Bemcentinib. These approaches provided compelling evidence that AXL promotes LEC migration in both 2D and 3D culture systems. Our findings demonstrated that AXL activation was induced by VEGF-C (Vascular Endothelial Growth Factor C) and further amplified downstream signaling via the AKT pathway. In vivo, the role of AXL in lymphatic vessel sprouting was demonstrated using R428 in a model of VEGF-C-induced lymphangiogenesis in lymph nodes. Interestingly, we discovered that AXL was predominantly expressed in MARCO+ LECs. Strikingly, under metastatic conditions, there was a notable increase in the density and penetration extent of these AXL-expressing LECs into the lymph node parenchyma. Collectively, our findings pinpoint AXL as a potent enhancer of lymphangiogenesis operating through the VEGF-C/AKT pathway. Furthermore, the identification of AXL expression within a distinct LEC subpopulation, particularly in the context of metastasis, underscores the intricate interplay between AXL signaling and lymphatic dynamics within the lymph node microenvironment.

Emerging roles of intratumoral microbiota: a key to novel cancer therapies

Microorganisms, including bacteria, viruses, and fungi, have been found to play critical roles in tumor microenvironments. Due to their low biomass and other obstacles, the presence of intratumor microbes has been challenging to definitively establish. However, advances in biotechnology have enabled researchers to reveal the association between intratumor microbiota and cancer. Recent studies have shown that tumor tissues, once thought to be sterile, actually contain various microorganisms. Disrupted mucosal barriers and adjacent normal tissues are important sources of intratumor microbiota. Additionally, microbes can invade tumors by traveling through the bloodstream to the tumor site and infiltrating through damaged blood vessels. These intratumor microbiota may promote the initiation and progression of cancers by inducing genomic instability and mutations, affecting epigenetic modifications, activating oncogenic pathways, and promoting inflammatory responses. This review summarizes the latest advancements in this field, including techniques and methods for identifying and culturing intratumor microbiota, their potential sources, functions, and roles in the efficacy of immunotherapy. It explores the relationship between gut microbiota and intratumor microbiota in cancer patients, and whether altering gut microbiota might influence the characteristics of intratumor microbiota and the host immune microenvironment. Additionally, the review discusses the prospects and limitations of utilizing intratumor microbiota in antitumor immunotherapy.

Design strategies and biomedical applications of organic NIR-IIb fluorophores

The introduction of fluorescence imaging (FLI) in near-infrared II sub-channels (NIR-IIb, 1500-1700 nm) has revolutionized the ability to explore complex patho-physiological settings in vivo. Despite the transformative potentials, the development of organic NIR IIb dyes encounters considerable difficulties, and only a limited number of such fluorophores have been developed so far. This review systematically introduces design strategies of organic NIR-IIb fluorophores classified by molecular scaffolds, mainly including cyanine dyes and D-A-D small molecule dyes. The design strategies of cyanine dyes involve repurposing of the existing NIR dyes, conjugate reinforcement and regulation of the aggregation state. For D-A-D small molecule dyes, strategies mainly incorporate the extension of the conjugate skeleton, introduction of shielding units, and acceptor/donor engineering. We further describe recent biomedical applications including biomedical imaging and imaging-guided therapy, and conclude by clarifying the current challenges and prospects of NIR-IIb FLI.

A multistage drug delivery approach for colorectal primary tumors and lymph node metastases

The presence of lymph node (LN) metastases guides cancer staging and worsens prognoses. Incomplete lymphadenectomy of metastatic LNs may end up with disease recurrence, while excessive resection can result in increased postoperative complications with even no survival benefit. Thus, effective non-invasive methods to treat metastatic LNs would be highly desirable. Here, we develop an enzyme-responsive formulation of small-sized doxorubicin-loaded mesoporous silica nanoparticles (DMSN, 40 nm) encapsulated in nanoliposomes (DMSN@Pla-Lipo, 160 nm). The liposomal membrane contains 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), two phospholipids sensitive to secreted phospholipase A2 in human colorectal tumors. In an orthotopic colorectal murine tumor model, phospholipase-induced membrane permeabilization triggers the liberation of DMSN from liposomes for enhanced tumor penetration, conferring an enhanced suppression for the primary tumor. Furthermore, through translocation into metastatic LNs via tumor lymphatics, metastatic tumor cells in LNs are eradicated. Metastases to other major organs are also suppressed, which can be ascribed to the inhibition of colorectal cancer metastasis-associated TGF-β, Wnt, and Hippo signaling pathways in metastatic LNs. The treatment confers an 80% 90-day survival rate in this aggressive tumor model. Taken together, this study demonstrates a deliberate treatment approach for management of both primary tumors and metastatic LNs through multistage drug delivery.

Trade-off movement between hydraulic resistance escape and shear stress escape by cancer cells

In the circulatory system, the microenvironment surrounding cancer cells is complex and involves multiple coupled factors. We selected two core physical factors, shear stress and hydraulic resistance, and constructed a microfluidic device with dual negative inputs to study the trade-off movement behavior of cancer cells when facing coupled factors. We detected significant shear stress escape phenomena in the MDA-MB-231 cell line and qualitatively explained this behavior using a cellular force model. Through the dual validation of substrate anti-cell-adhesion modification and employment of the MCF-7 cell line, we further substantiated the predictability and feasibility of our model. This study provides an explanation for the trade-off underlying the direction-choosing mechanism of cancer cells when facing environmental selection.

Multi-Institutional Analysis of Survival and Recurrence Patterns of Different Pathological Regression Types After Neoadjuvant Chemoradiotherapy or Radiotherapy for Esophageal Squamous Cell Carcinoma

BACKGROUND

The recurrence patterns of different types of pathologic regression of the primary tumor and lymph nodes in patients with esophageal squamous cell carcinoma (ESCC) after neoadjuvant chemoradiotherapy (NCRT) are little known, especially in ypT0N+ patients.

METHODS

We included 582 patients with ESCC who had esophagectomy after NCRT or neoadjuvant radiotherapy (NRT) from 3 institutions. The patients were divided into 4 groups: ypT0N0, ypT0N+, ypT+N0, and ypT+N+ according to the type of pathological regression of the primary tumor and lymph nodes. Survival, recurrence pattern and timing, and potential prognostic factors were compared.

RESULTS

A total of 179 patients were classified as ypT0N0, 227 patients as ypT + N0, 45 patients as ypT0N+, and 131 patients as ypT + N+. The median follow-up was 31.7 months in all patients. The restricted mean survival time (RMST) of ypT0N0, ypT + N0, ypT0N+, and ypT + N+ patients decreased sequentially (70.64, 63.84, 55.93 and 39.96 months) and the recurrence rates increased sequentially (22.3%, 29.5%, 44.4% and 54.2%). Both the overall survival (OS) and recurrence-free survival (RFS) in the ypT0N+ group were significantly lower than those in the ypT0N0 group (HR: 2.226, p = 0.007; HR: 2.271, p = 0.003). The distant metastasis (DM) pattern in ypT0N+ was similar to that of ypT + N+, and higher than that of ypN0 (25.6% vs 14.3%, HR: 1.970, p = 0.040).

CONCLUSIONS

ESCC patients with various pathological regression types after receiving NCRT or NRT had significantly different survival rates. ypT0N+ patients had a lower survival rate and higher DM rate than ypT0N0 patients. For these lymph node-positive patients, adjuvant chemotherapy does not appear to improve their prognosis.

The ending is not the end: Lymph node metastasis in oral squamous cell carcinoma

Lymph node metastasis is an important biological feature of oral squamous cell carcinoma, bearing poorly prognostic implications. However, the role of lymph node metastasis in cancer progression remains inconclusive. On the one hand, lymph nodes are pivotal sites for initiating specific immunity, which is crucial for maintaining antitumor immune response. On the other hand, they also serve as primary conduits for tumor metastasis, with lymph node colonization potentially inducing systemic immune dysfunction, thereby further promoting tumor progression. Considering this paradoxical role of lymph nodes, comprehending their impact on the primary tumor and immunity becomes paramount. Furthermore, leveraging these distinctive attributes of lymph nodes presents novel avenues for enhancing current therapeutic strategies against oral squamous cell carcinoma. This review summarizes the anatomical and molecular profiles of lymph node metastasis in oral squamous cell carcinoma, elucidating how lymphatic involvement compromises antitumor immunity, thus facilitating primary tumor and distant metastases. Additionally, it explores avenues for harnessing these mechanisms to optimize clinical interventions.

Mutant Pattern of p53 as a Feasible Predictor of Distant Metastasis Following Curative Gastrectomy for Advanced-stage Gastric Cancer

Objective: The TP53 mutation is a poor prognostic factor for malignant tumors in a number of organs. The present study primarily aimed to clarify the impact of the mutant pattern of p53 on the prognosis and recurrence of gastric cancer. Methods: For this purpose, 519 patients who underwent radical gastrectomy for cancer were enrolled in the present study. Immunohistochemistry (IHC) was used to examine p53 expression in tissues and a three-stage classification system was used to divide the patient tissues into three groups according to the expression of p53: Heterogeneous (wild-type), absent and overexpression (mutant). Results: After 5 years of follow-up, recurrence and metastasis occurred in 38.7% of patients with stomach cancer, with a p53 mutant pattern in 48.4% of these patients. Patients with a p53 mutant pattern had lower recurrence-free and overall survival rates at 5 years compared with those who were p53 wild-type (P<0.001). It was found that the p53 pattern differed significantly (P<0.001) between the wild-type and mutant patterns, including the pN0 and pN+ gastric cancer subgroups (P<0.001 and P=0.014, respectively). The p53 mutant pattern was also significant in the determination of the recurrence-free survival of patients with progressive stomach cancer (P<0.0001). The 5-year overall survival rates were 71.7 and 36.2%, and the recurrence-free survival rates were 71.2 and 35.2% in the pN0 and pN+ groups, respectively (P<0.001). The mutant pattern of p53 was a significant prognostic factor for both distant metastasis [relative risk (RR)=2.881, P<0.001] and overall survival (RR=2.809, P<0.001) in the univariate Cox regression analysis. In the multivariate analysis, distant metastasis (RR=2.767, P<0.001) remained significant in the mutant pattern of p53 staining. After propensity score matching, 189 patients with a p53 wild-type and 189 patients with a p53 mutant pattern were extracted for analysis. The 5-year overall survival rate in patients with the p53 mutant pattern (n = 189) was worse than that in the patients with p53 wild-type (n = 189) and with significant differences (log-rank P<0.01). The study was statistically significant after Cox univariate and multivariate regression analysis, which revealed that the mutant pattern of p53 is an independent prognostic factor impacting distant metastases following curative gastrectomy for advanced-stage gastric cancer (p = 0.48).

VEGF-C propagates 'onward' colorectal cancer metastasis from liver to lung

BACKGROUND

The formation of lung metastasis as part of the progression of colon cancer is a poorly understood process. Theoretically, liver metastases could seed lung metastases.

METHODS

To assess the contribution of the liver lymphatic vasculature to metastatic spread to the lungs, we generated murine liver-metastasis-derived organoids overexpressing vascular endothelial growth factor (VEGF)-C. The organoids were reimplanted into the mouse liver for tumour generation and onward metastasis.

RESULTS

Liver metastases from patients with concomitant lung metastases showed higher expression of VEGF-C, lymphatic vessel hyperplasia, and tumour cell invasion into lymphatic vessels when compared to those without lung metastases. Reimplantation of VEGF-C overexpressing organoids into the mouse liver showed that VEGF-C caused peritumoral lymphatic vessel hyperplasia, lymphatic tumour cell invasion, and lung metastasis formation. This change in metastatic organotropism was accompanied by reduced expression of WNT-driven adult stem cell markers, and increased expression of fetal stem cell markers and NOTCH pathway genes. Further NOTCH pathway inhibition with γ-secretase inhibitor (DAPT) in vivo results in a slight reduction in lung metastases and a decrease in lymphatic hyperplasia and invasion in VEGF-C-overexpressing tumours.

CONCLUSION

Collectively, these data indicate that VEGF-C can drive onward metastasis from the liver to the lung and suggest that targeting VEGF-C/NOTCH pathways may impair the progression of colorectal cancer.

Spatiotemporal Mapping of Lymphatic Metastases in Gastric Cancer Using Tumor-Trackable and Enzyme-Activatable Near-Infrared Fluorescent Nanoprobes

Sentinel lymph node biopsy holds significant importance in cancer management, yet the challenge persists in early detection and precise resection of metastasis lymph nodes (LNs) due to the absence of specific and sensitive optical probes. This study reports metastatic LN reporters (MLRs) with an activatable optical output for accurate spatiotemporal mapping of lymphatic metastases in gastric cancer. MLRs are self-assembled entities incorporating mixed amphiphiles with a lipophilic tail and a tumor-targeting ligand or a fluorescent moiety that is caged with a switch cleavable by tumor-specific β-galactosidase (β-Gal). After draining into LNs, MLRs selectively activate their near-infrared fluorescence in the presence of spreading tumor cells. In orthotopic gastric cancer mouse models, the representative reporter MLR1 distinguishes macro/micrometastatic LNs from benign LNs and enables early detection of skip LNs metastasis patterns in a spatial-dependent manner. Such an active sensing mechanism provides a high level of sensitivity and specificity comparable to those of flow cytometry analysis. In surgically resected patient specimens, MLR1 differentiates cancerous tissues and metastatic LNs from normal tissues and benign LNs within 1 h. This study thus presents NIRF nanoprobes that permit facile detection of LN metastases in GC patient samples and highlights a generic translatable nanoprobe design for understanding metastatic progression.

Cancer immunotherapy response persists after lymph node resection

Lymphatic transport facilitates the presentation of cancer antigens in tumor-draining lymph nodes (tdLNs), leading to T cell activation and the generation of systemic antitumor immune surveillance. Surgical removal of LNs to control cancer progression is routine in clinical practice. However, whether removing tdLNs impairs immune checkpoint blockade (ICB) is still controversial. Our analysis demonstrates that melanoma patients remain responsive to PD-1 checkpoint blockade after LN dissection. We were able to recapitulate the persistent response to ICB after complete LN resection in murine melanoma and mammary carcinoma models. Mechanistically, soluble antigen and antigen-carrying migratory dendritic cells are diverted to non-directly tumor draining LNs (non-tdLNs) after tdLN dissection. Consistently, robust ICB responses in patients with head and neck cancer after primary tumor and tdLN resection correlated with the presence of reactive LNs in distant areas. These findings indicate that non-tdLNs sufficiently compensate for the removal of direct tdLNs and sustain the response to ICB.

Cancer treatments as paradoxical catalysts of tumor awakening in the lung

Much of the fatality of tumors is linked to the growth of metastases, which can emerge months to years after apparently successful treatment of primary tumors. Metastases arise from disseminated tumor cells (DTCs), which disperse through the body in a dormant state to seed distant sites. While some DTCs lodge in pre-metastatic niches (PMNs) and rapidly develop into metastases, other DTCs settle in distinct microenvironments that maintain them in a dormant state. Subsequent awakening, induced by changes in the microenvironment of the DTC, causes outgrowth of metastases. Hence, there has been extensive investigation of the factors causing survival and subsequent awakening of DTCs, with the goal of disrupting these processes to decrease cancer lethality. We here provide a detailed overview of recent developments in understanding of the factors controlling dormancy and awakening in the lung, a common site of metastasis for many solid tumors. These factors include dynamic interactions between DTCs and diverse epithelial, mesenchymal, and immune cell populations resident in the lung. Paradoxically, among key triggers for metastatic outgrowth, lung tissue remodeling arising from damage induced by the treatment of primary tumors play a significant role. In addition, growing evidence emphasizes roles for inflammation and aging in opposing the factors that maintain dormancy. Finally, we discuss strategies being developed or employed to reduce the risk of metastatic recurrence.

Lymphovascular Tumoral Emboli in Inflammatory Breast Cancer Result from Haptotaxis-Mediated Encircling Lymphangiogenesis

Inflammatory breast cancer (IBC) is characterized by numerous tumor emboli within lymphatics. In a recent study, we observed tumor embolic budding both in vitro and in vivo within lymphovascular spaces and proposed this to account for the plethora of tumor emboli seen in IBC. These observations did not address, however, how lymphovascular invasion is initiated or the mechanisms involved. In the present study, using the well-characterized patient-derived xenograft (PDX), Mary-X, which exhibited florid lymphovascular invasion (LVI) in athymic mice (LVI) as defined by E-cadherin-positive tumor emboli within lymphatic channels distinguished by podoplanin and LYVE1 membrane and Prox1 nuclear immunoreactivities and spontaneous spheroidgenesis in vitro and human cases of IBC which showed similar LVI, we compared laser-captured microdissected emboli from Mary-X and from the cases of human IBC to non-embolic areas. Mary-X and IBC emboli expressed high levels of E-cadherin and no evidence of epithelial-mesenchymal transition (EMT). Mary-X spheroids expressed high levels of VEGF, especially VEGF-C, and stimulated both vascular and lymphatic endothelial haptotaxis. We then transplanted Mary-X serially into green, cyano, red, and nestin-green fluorescing protein (GFP-, CFP-, RFP-, and nestin-GFP) transgenic reporter mice in various combinations. Multicolor murine imaging studies indicated that reporter-labeled stroma initially encircled clumps of tumor cells and then served as a scaffold that supported nestin-GFP-labeled endothelial haptotaxis resulting in encircling lymphangiogenesis, confirmed by dual LYVE1 immunofluorescence. The present studies demonstrate a possible mechanism of a critical step of the tumor emboli formation of IBC.

The Molecular Evolution of Melanoma Distant Metastases

The evolution of primary melanoma to lymph node and distant metastasis is incompletely understood. We examined the genomic diversity in melanoma progression in matched primary melanomas and lymph node and distant metastases from 17 patients. FISH analysis revealed cancer cell fractions with monotonic copy number alterations, including PHIP gain and PTEN loss, in the metastatic cascade. By contrast, the cancer cell fraction with copy number alterations for BPTF and MITF was reduced in lymph node metastases but increased in distant metastases. Separately, the cancer cell fraction with NCOA3 copy number alteration was comparable between primary tumors and lymph node metastases yet increased in distant metastases. These results suggest enrichment of the phosphoinositide 3-kinase and MITF pathways in the transition through the metastatic cascade. By contrast, next-generation sequencing analysis did not identify a consistent pattern of changes in variant allele frequency while revealing several intriguing findings, including decreased variant allele frequency in distant metastases and distinct drivers in lymph node versus distant metastases. These results provide evidence that distant melanoma metastasis does not always emanate from lymph node metastasis. These results enhance our understanding of clonal patterns of melanoma metastasis, with possible implications for targeted therapy and metastasis competency.

The role of ferroptosis resistance in lymph-associated tumour metastasis

Tumour metastasis is a crucial factor in determining clinically challenging tumours. In this respect, the lymphatic system may act as potential entry portals for tumour metastasis, whilst, clinical detection of tumour-infiltrated lymph nodes also indicates poorer prognosis and higher metastatic risk. Whether tumour cells gain ferroptosis resistance in lymph that make them exhibit a stronger propensity for lymphatic dissemination compared to hematogenous spread might be a breakthrough for elucidating lymph-associated tumour metastasis. This review discusses how the lymphatic system endows tumour cells with ferroptosis resistance character, which makes them more propensity for lymph node pre-metastasis and distant metastasis through lymphatic circulation. Comprehensively considering the distinct structure and property of lymph and the unique metabolic characteristics of tumours, all of the lymphatic vessels, intestinal lymph and lymph nodes collectively manipulate an intricate interaction with the hematogenous system and afford substances exchange with tumour cells and extracellular vesicles, upon which make a ferroptosis resistant microenvironment for subsequent metastasis in distant organs and lymph nodes.

Predicting non-small cell lung cancer lymph node metastasis: integrating ctDNA mutation/methylation profiling with positron emission tomography-computed tomography (PET-CT) scan: protocol for a prospective clinical trial (LUNon-invasive Study)

Background

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer cases and remains a leading cause of cancer-related death. Lymph node metastasis (LNM) significantly affects recurrence, survival rates, and treatment options. While lymph node sampling is standard for surgically removing operable NSCLC, it can lead to complications. Positron emission tomography-computed tomography (PET-CT) helps assess preoperative LNM despite false positive or negative rates. Additionally, circulating tumor DNA (ctDNA) detects minimal residual disease with high sensitivity and specificity. Whether ctDNA can predict LNM in operable NSCLC remains uncertain. Our goal is to develop a precise model for predicting NSCLC LNM using non-invasive ctDNA/methylation profiling combined with PET-CT imaging.

Methods

This is a prospective study conducted in three stages. We will enroll patients with clinical stage I-IIIB [8th tumor, node, metastasis (TNM) staging] NSCLC requiring lobectomy plus lymph node sampling/dissection. The distribution of clinical stages in the enrolled population is as follows: clinical stage cN0 (n=100) and cN1/cN2 (n=100). During Stage 1, we will establish LNMs-specific ctDNA methylation signatures and compare negative predictive value (NPV) rates of LNMs using preoperative blood ctDNA somatic mutation/methylation alone or combined with PET-CT across different groups. For Stage 2, we will compare detection rates between ctDNA somatic mutation/methylation profiles alone or combined with PET-CT and traditional mediastinoscopy/endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). As for Stage 3, ctDNA-free interval (CFI) and disease-free survival between systematic lymph node presence and absence in patients will be compared with preoperative negative ctDNA profiling and/or PET-CT. In Stage 3, patients will be followed up for 5 years to collect recurrence and survival data. Post-surgery follow-up ctDNA tests will be conducted every 3 months for the first 2 years, every 6 months for years 3-4, and annually in year five. Demographics and baseline data will be summarized with mean, standard deviation, median, max, and min values. Tests will include t-tests, Welch/Behren-Fisher test, and Wilcoxon rank-sum test for continuous variables. Categorical data will be presented as counts/percentages and compared using χ2 test or Fisher's exact test.

Discussion

By utilizing preoperative ctDNA/methylation profiling in conjunction with PET-CT, this study is expected to yield substantial evidence for accurately predicting LNM before surgery. This will help inform surgeons in selecting the appropriate intraoperative lymph node dissection strategy for operable NSCLC patients.

Trial Registration

This study is registered on www.clinicaltrials.gov (NCT06358222).

Molecular features of NSCLC patients with liver metastasis

Background

Metastasis is the primary cause of lung cancer-related death. Primary cancer cells invade through the lymphatic or blood vessels to distant sites. Recently, it was proposed that lymphatic metastasis was more a hallmark of tumor aggressiveness or metastatic potential than a gateway to metastases. Therefore, the underlying molecular mechanism of metastasis is not entirely clear.

Objectives

This study aimed to explore the genetic mechanisms underlying liver metastases from lung cancer and to evaluate the efficacy of different therapies in these patients.

Design

We retrospectively analyzed the mutation spectrum of different biopsy samples including primary lung tumors, liver, lymph node metastasis, and circulating tumor DNA (ctDNA) from 1090 non-small-cell lung cancer (NSCLC) patients with liver metastasis between the years 2017 and 2022.

Methods

Demographic and disease characteristics were summarized using descriptive parameters. Time to treatment discontinuation was used to analyze the clinical outcome.

Results

More liquid biopsies were performed than tissue biopsies, especially in the treated advanced NSCLC patients. Liver metastasis before treatment was associated with poor response to immune checkpoint inhibitors and targeted therapy. Liver and lymph node metastasis had higher levels of single nucleotide variants and copy number variants than primary lung tumors. In paired lung and liver, lymph nodes, and simultaneous ctDNA, we found actionable mutations were always shared, while metastasis samples had multiple private mutations. Serial ctDNA analysis identifies potential resistant mutations and describes the evolution of tumor cells.

Conclusion

Liver and lymph node metastasis in NSCLC showed shared actionable mutations. Of note, the discrepancy of private mutations in liver and lymph node metastases indicated that liver metastases are mainly seeded by the primary tumor rather than the earlier colonized lymph node metastases.

Mechanisms of lymph node metastasis: An extracellular vesicle perspective

In several solid tumors such as breast cancer, prostate cancer, colorectal cancer or melanoma, tumor draining lymph nodes are the earliest tissues where colonization by tumor cells is detected. Lymph nodes act as sentinels of metastatic dissemination, the deadliest phase of tumor progression. Besides hematogenous dissemination, lymphatic spread of tumor cells has been demonstrated, adding more complexity to the mechanisms involved in metastasis. A network of blood and lymphatic vessels surrounds tumors providing routes for tumor soluble factors to mediate regional and long-distance effects. Additionally, extracellular vesicles (EVs), particularly small EVs/exosomes, have been shown to circulate through the blood and lymph, favoring the formation of pre-metastatic niches in the tumor-draining lymph nodes (TDLNs) and distant organs. In this review, we present an overview of the relevance of lymph node metastasis, the structural and immune changes occurring in TDLNs during tumor progression, and how extracellular vesicles contribute to modulating some of these alterations while promoting the formation of lymph node pre-metastatic niches.

Lymphatic system regulation of anti-cancer immunity and metastasis

Cancer dissemination to lymph nodes (LN) is associated with a worse prognosis, increased incidence of distant metastases and reduced response to therapy. The LN microenvironment puts selective pressure on cancer cells, creating cells that can survive in LN as well as providing survival advantages for distant metastatic spread. Additionally, the presence of cancer cells leads to an immunosuppressive LN microenvironment, favoring the evasion of anti-cancer immune surveillance. However, recent studies have also characterized previously unrecognized roles for tumor-draining lymph nodes (TDLNs) in cancer immunotherapy response, including acting as a reservoir for pre-exhausted CD8+ T cells and stem-like CD8+ T cells. In this review, we will discuss the spread of cancer cells through the lymphatic system, the roles of TDLNs in metastasis and anti-cancer immune responses, and the therapeutic opportunities and challenges in targeting LN metastasis.

Drug Combination Nanoparticles Containing Gemcitabine and Paclitaxel Enable Orthotopic 4T1 Breast Tumor Regression

Early diagnosis, intervention, and therapeutic advancements have extended the lives of breast cancer patients; however, even with molecularly targeted therapies, many patients eventually progress to metastatic cancer. Recent data suggest that residual breast cancer cells often reside in the lymphatic system before rapidly spreading through the bloodstream. To address this challenge, an effective drug combination composed of gemcitabine (G) and paclitaxel (T) is administered intravenously in sequence at the metastatic stage, but intravenous GT infusion may limit lymphatic GT drug accessibility and asynchronous drug exposure in cancer cells within the lymph. To determine whether co-localization of intracellular gemcitabine and paclitaxel (referred to as GT) could overcome these limitations and enhance the efficacy of GT, we have evaluated a previously reported GT drug-combination formulated in nanoparticle (referred to as GT-in-DcNP) evaluated in an orthotopic breast tumor model. Previously, with indocyanine green-labeled nanoparticles, we reported that GT-in-DcNP particles after subcutaneous dosing were taken up rapidly and preferentially into the lymph instead of blood vessels. The pharmacokinetic study showed enhanced co-localization of GT within the tumors and likely through lymphatic access, before drug apparency in the plasma leading to apparent long-acting plasma time-course. The mechanisms may be related to significantly greater inhibitions of tumor growth-by 100 to 140 times-in both sub-iliac and axillary regions compared to the equivalent dosing with free-and-soluble GT formulation. Furthermore, GT-in-DcNP exhibited dose-dependent effects with significant tumor regression. In contrast, even at the highest dose of free GT combination, only a modest tumor growth reduction was notable. Preliminary studies with MDA-231-HM human breast cancer in an orthotopic xenograft model indicated that GT-in-DcNP may be effective in suppressing human breast tumor growth. Taken together, the synchronized delivery of GT-in-DcNP to mammary tumors through the lymphatic system offers enhanced cellular retention and greater efficacy.

Associations amongst genes, molecules, cells, and organs in breast cancer metastasis

This paper is a cross fertilization of ideas about the importance of molecular aspects of breast cancer metastasis by basic scientists, a pathologist, and clinical oncologists at the Henry Ford Health symposium. We address four major topics: (i) the complex roles of lymphatic endothelial cells and the molecules that stimulate them to enhance lymph node and systemic metastasis and influence the anti-tumor immunity that might inhibit metastasis; (ii) the interaction of molecules and cells when breast cancer spreads to bone, and how bone metastases may themselves spread to internal viscera; (iii) how molecular expression and morphologic subtypes of breast cancer assist clinicians in determining which patients to treat with more or less aggressive therapies; (iv) how the outcomes of patients with oligometastases in breast cancer are different from those with multiple metastases and how that could justify the aggressive treatment of these patients with the hope of cure.

Cancer metastasis through the lymphatic versus blood vessels

Whether cancer cells metastasize from the primary site to the distant sites via the lymphatic vessels or the blood vessels directly into the circulation is still under intense study. In this review article, we follow the journey of cancer cells metastasizing to the sentinel lymph nodes and beyond to the distant sites. We emphasize cancer heterogeneity and microenvironment as major determinants of cancer metastasis. Multiple molecules have been found to be associated with the complicated process of metastasis. Based on the large sentinel lymph node data, it is reasonable to conclude that cancer cells may metastasize through the blood vessels in some cases but in most cases, they use the sentinel lymph nodes as the major gateway to enter the circulation to distant sites.

Interrogating the roles of lymph node metastasis in systemic immune surveillance

Lymph nodes (LNs) are principal orchestrators of the adaptive immune response, yet in the context of malignancy, they are typically the first sites of metastasis. When tumors spread to LNs, they alter the immune repertoire, ultimately reconditioning it in a manner that suppresses anti-tumor immunity and promotes further metastatic dissemination. Conversely, activation of anti-tumor immunity within LNs is essential for immunotherapy, suggesting clinical approaches to radiotherapy in LNs and lymphadenectomy may need to be reconsidered in the context of immune checkpoint blockade (ICB). Herein, we discuss our understanding of the immune remodeling that coincides with LN metastasis as well as recent clinical studies exploring neoadjuvant immunotherapy and the roles of LNs in treatment of solid organ malignancies.

The hybrid nanosystem for the identification and magnetic hyperthermia immunotherapy of metastatic sentinel lymph nodes as a multifunctional theranostic agent

Lymphatic metastasis is the main cause of early-stage tumor spread, making the identification and therapy of metastatic sentinel lymph nodes (SLNs) are highly desirable in clinic. Currently, suspected malignant SLNs typically undergo a series of independent operations in clinical practice, including imaging, staining, sentinel lymph node biopsy (SLNB) and lymph node dissection (LND), which brings inconvenience to diagnosis and treatment, and may cause postoperative complications for patients. Moreover, the ordinary removal of tumor-draining lymph nodes (TDLNs) may do harm to systemic immunity required for tumor eradication. Hence, we utilized the hybrid nanosystem (SPIOs + RPPs) we constructed before for the integrated staining, ultrasound imaging, and therapy of metastatic SLNs. In this study, SPIOs + RPPs could migrate into SLNs successfully to stain them black for easy visual identification. Beyond staining, the hybrid nanosystem could realize contrast enhanced ultrasound (CEUS) imaging in SLNs. Meanwhile, it could inhibit cancer cells to lower the tumor burden and reverse immune-suppressive microenvironment of metastatic SLNs effectively via magnetic hyperthermia immunotherapy in VX2 tumor-bearing rabbits with popliteal fossa lymph node metastasis. These findings indicate that SPIOs + RPPs is a potential multifunctional theranostic agent for detection and therapy of lymphatic metastasis.

Ex vivo model of breast cancer cell invasion in live lymph node tissue

Lymph nodes (LNs) are common sites of metastatic invasion in breast cancer, often preceding spread to distant organs and serving as key indicators of clinical disease progression. However, the mechanisms of cancer cell invasion into LNs are not well understood. Existing in vivo models struggle to isolate the specific impacts of the tumor-draining lymph node (TDLN) milieu on cancer cell invasion due to the co-evolving relationship between TDLNs and the upstream tumor. To address these limitations, we used live ex vivo LN tissue slices with intact chemotactic function to model cancer cell spread within a spatially organized microenvironment. After showing that BRPKp110 breast cancer cells were chemoattracted to factors secreted by naïve LN tissue in a 3D migration assay, we demonstrated that ex vivo LN slices could support cancer cell seeding, invasion, and spread. This novel approach revealed dynamic, preferential cancer cell invasion within specific anatomical regions of LNs, particularly the subcapsular sinus (SCS) and cortex, as well as chemokine-rich domains of immobilized CXCL13 and CCL1. While CXCR5 was necessary for a portion of BRPKp110 invasion into naïve LNs, disruption of CXCR5/CXCL13 signaling alone was insufficient to prevent invasion towards CXCL13-rich domains. Finally, we extended this system to pre-metastatic TDLNs, where the ex vivo model predicted a lower invasion of cancer cells. The reduced invasion was not due to diminished chemokine secretion, but it correlated with elevated intranodal IL-21. In summary, this innovative ex vivo model of cancer cell spread in live LN slices provides a platform to investigate cancer invasion within the intricate tissue microenvironment, supporting time-course analysis and parallel read-outs. We anticipate that this system will enable further research into cancer-immune interactions and allow isolation of specific factors that make TDLNs resistant to cancer cell invasion, which are challenging to dissect in vivo.

Identification of activating transcription factor 6 (ATF6) as a novel prognostic biomarker and potential target in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is originating from oral mucosal epithelial cells. Autophagy plays a crucial role in cancer treatment by promoting cellular self-degradation and eliminating damaged components, thereby enhancing therapeutic efficacy. In this study, we aim to identify a novel autophagy-related biomarker to improve OSCC therapy.

METHODS

We firstly utilized Cox and Lasso analyses to identify that ATF6 is associated with OSCC prognosis, and validated the results by Kaplan-Meier survival analysis. We further identified the downstream pathways and related genes by enrichment analysis and WGCNA analysis. Subsequently, we used short interfering RNA to investigate the effects of ATF6 knockdown on proliferation, migration, apoptosis, and autophagy in SCC-9 and SCC-15 cells through cell viability assay, transwell assay, EdU incorporation assay, flow cytometry analysis, western blot analysis and immunofluorescence analysis, etc. RESULTS: Bioinformatics analyses showed that ATF6 overexpression was associated with prognosis and detrimental to survival. In vitro studies verified that ATF6 knockdown reduced OSCC cell proliferation and migration. Mechanistically, ATF6 knockdown could promote cellular autophagy and apoptosis.

CONCLUSION

We propose that ATF6 holds potential as a prognostic biomarker linked to autophagy in OSCC. This study provides valuable clues for further exploration of targeted therapy against OSCC.

Stepwise Ultra-pH-Sensitive Micelles Overcome a pKa Barrier for Systemic Lymph Node Delivery

While local nanoparticle delivery to lymph nodes is well studied, there are few design criteria for intravenous delivery to the entire lymph node repertoire. In this study, we investigated the effect of NP pH transition on lymph node targeting by employing a series of ultra-pH-sensitive (UPS) polymeric micelles. The UPS library responds to pH thresholds (pKa 6.9, 6.2, and 5.3) over a range of physiological pH. We observed a dependence of intravenous lymph node targeting on micelle pH transition. UPS6.9 (subscript indicates pKa) shows poor lymph node delivery, while UPS5.3 delivers efficiently to lymph node sets. We investigated targeting mechanisms of UPS5.3, observing an accumulation among lymph node lymphatics and a dependence on lymph node-resident macrophages. To overcome the pH-threshold barrier, which limits UPS6.9, we rationally designed a nanoparticle coassembly of UPS6.9 with UPS5.3, called HyUPS. The HyUPS micelle retains the constitutive pH transitions of each polymer, showing stepwise responses to discrete pH thresholds. We demonstrate that HyUPS improves UPS6.9 delivery to lymph nodes, extending this platform for disease detection of lymph node metastasis.

Oleic acid-PPARγ-FABP4 loop fuels cholangiocarcinoma colonization in lymph node metastases microenvironment

BACKGROUND AND AIMS

Lymph node metastasis is a significant risk factor for patients with cholangiocarcinoma, but the mechanisms underlying cholangiocarcinoma colonization in the lymph node microenvironment remain unclear. We aimed to determine whether metabolic reprogramming fueled the adaptation and remodeling of cholangiocarcinoma cells to the lymph node microenvironment.

APPROACH AND RESULTS

Here, we applied single-cell RNA sequencing of primary tumor lesions and paired lymph node metastases from patients with cholangiocarcinoma and revealed significantly reduced intertumor heterogeneity and syntropic lipid metabolic reprogramming of cholangiocarcinoma after metastasis to lymph nodes, which was verified by pan-cancer single-cell RNA sequencing analysis, highlighting the essential role of lipid metabolism in tumor colonization in lymph nodes. Metabolomics and in vivo CRISPR/Cas9 screening identified PPARγ as a crucial regulator in fueling cholangiocarcinoma colonization in lymph nodes through the oleic acid-PPARγ-fatty acid-binding protein 4 positive feedback loop by upregulating fatty acid uptake and oxidation. Patient-derived organoids and animal models have demonstrated that blocking this loop impairs cholangiocarcinoma proliferation and colonization in the lymph node microenvironment and is superior to systemic inhibition of fatty acid oxidation. PPARγ-regulated fatty acid metabolic reprogramming in cholangiocarcinoma also contributes to the immune-suppressive niche in lymph node metastases by producing kynurenine and was found to be associated with tumor relapse, immune-suppressive lymph node microenvironment, and poor immune checkpoint blockade response.

CONCLUSIONS

Our results reveal the role of the oleic acid-PPARγ-fatty acid-binding protein 4 loop in fueling cholangiocarcinoma colonization in lymph nodes and demonstrate that PPARγ-regulated lipid metabolic reprogramming is a promising therapeutic target for relieving cholangiocarcinoma lymph node metastasis burden and reducing further progression.

Prognostic effect of TCF1+ CD8+ T cell and TOX+ CD8+ T cell infiltration in lung adenocarcinoma

Recent studies have highlighted the pivotal roles of T cell transcription factors TCF-1 and TOX in modulating the immune response in cancer, with TCF-1 maintaining CD8+ T cell stemness and TOX promoting T cell exhaustion. The prognostic significance of these factors in lung adenocarcinoma (LUAD) remains a critical area of investigation. The retrospective study included 191 patients with LUAD who underwent surgery, of whom 83% were in stages II and III. These patients were divided into exploratory (n = 135) and validation (n = 56) groups based on the time of diagnosis. Multiplex fluorescence immunohistochemistry was used to examine the infiltration levels of CD8+ T cells, TCF1+ CD8+ T cells, and TOX+ CD8+ T cells. The percentage of CD8+ T cells in tumor was markedly lower than that in stroma (p < 0.05). In tumor-draining lymph nodes (TDLNs) invaded by tumor, the proportion of stem-like TCF1+ CD8+ T cells was significantly decreased (p < 0.01). Importantly, higher infiltration levels of CD8+ T cells and TCF1+ CD8+ T cells were associated with improved disease-free survival (DFS) (p = 0.009 and p = 0.006, respectively) and overall survival (OS) (p = 0.018 and p = 0.010, respectively). This study underscores the potential of TCF1+ CD8+ T cells as prognostic biomarkers in LUAD, providing insights into the tumor immune microenvironment and guiding future therapeutic strategies.

Immunological nanomaterials to combat cancer metastasis

Metastasis causes greater than 90% of cancer-associated deaths, presenting huge challenges for detection and efficient treatment of cancer due to its high heterogeneity and widespread dissemination to various organs. Therefore, it is imperative to combat cancer metastasis, which is the key to achieving complete cancer eradication. Immunotherapy as a systemic approach has shown promising potential to combat metastasis. However, current clinical immunotherapies are not effective for all patients or all types of cancer metastases owing to insufficient immune responses. In recent years, immunological nanomaterials with intrinsic immunogenicity or immunomodulatory agents with efficient loading have been shown to enhance immune responses to eliminate metastasis. In this review, we would like to summarize various types of immunological nanomaterials against metastasis. Moreover, this review will summarize a series of immunological nanomaterial-mediated immunotherapy strategies to combat metastasis, including immunogenic cell death, regulation of chemokines and cytokines, improving the immunosuppressive tumour microenvironment, activation of the STING pathway, enhancing cytotoxic natural killer cell activity, enhancing antigen presentation of dendritic cells, and enhancing chimeric antigen receptor T cell therapy. Furthermore, the synergistic anti-metastasis strategies based on the combinational use of immunotherapy and other therapeutic modalities will also be introduced. In addition, the nanomaterial-mediated imaging techniques (e.g., optical imaging, magnetic resonance imaging, computed tomography, photoacoustic imaging, surface-enhanced Raman scattering, radionuclide imaging, etc.) for detecting metastasis and monitoring anti-metastasis efficacy are also summarized. Finally, the current challenges and future prospects of immunological nanomaterial-based anti-metastasis are also elucidated with the intention to accelerate its clinical translation.