Increased Angiogenesis and Lymphangiogenesis in Metastatic Sentinel Lymph Nodes Is Associated With Nonsentinel Lymph Node Involvement and Distant Metastasis in Patients With Melanoma

Dual-Energy Computed Tomography in Detecting and Predicting Lymph Node Metastasis in Malignant Tumor Patients: A Comprehensive Review

The accurate and timely assessment of lymph node involvement is paramount in the management of patients with malignant tumors, owing to its direct correlation with cancer staging, therapeutic strategy formulation, and prognostication. Dual-energy computed tomography (DECT), as a burgeoning imaging modality, has shown promising results in the diagnosis and prediction of preoperative metastatic lymph nodes in recent years. This article aims to explore the application of DECT in identifying metastatic lymph nodes (LNs) across various cancer types, including but not limited to thyroid carcinoma (focusing on papillary thyroid carcinoma), lung cancer, and colorectal cancer. Through this narrative review, we aim to elucidate the clinical relevance and utility of DECT in the detection and predictive assessment of lymph node metastasis in malignant tumors, thereby contributing to the broader academic discourse in oncologic radiology and diagnostic precision.

Cross‑talk between lymphangiogenesis and malignant melanoma cells: New opinions on tumour drainage and immunization (Review)

Malignant melanoma (MM) is a highly aggressive tumour that can easily metastasize through the lymphatic system at the early stages. Lymph node (LN) involvement and lymphatic vessel (LV) density (LVD) represent a harbinger of an adverse prognosis, indicating a strong link between the state of the lymphatic system and the advancement of MM. Permeable capillary lymphatic vessels are the optimal conduits for melanoma cell (MMC) invasion, and lymphatic endothelial cells (LECs) can also release a variety of chemokines that actively attract MMCs expressing chemokine ligands through a gradient orientation. Moreover, due to the lower oxidative stress environment in the lymph compared with the blood circulation, MMCs are more likely to survive and colonize. The number of LVs surrounding MM is associated with tumour-infiltrating lymphocytes (TILs), which is crucial for the effectiveness of immunotherapy. On the other hand, MMCs can release various endothelial growth factors such as VEGF-C/D-VEGFR3 to mediate LN education and promote lymphangiogenesis. Tumour-derived extracellular vesicles are also used to promote lymphangiogenesis and create a microenvironment that is more conducive to tumour progression. MM is surrounded by a large number of lymphocytes. However, both LECs and MMCs are highly plastic, playing multiple roles in evading immune surveillance. They achieve this by expressing inhibitory ligands or reducing antigen recognition. In recent years, tertiary lymphoid structures have been shown to be associated with response to anti-immune checkpoint therapy, which is often a positive prognostic feature in MM. The present review discusses the interaction between lymphangiogenesis and MM metastasis, and it was concluded that the relationship between LVD and TILs and patient prognosis is analogous to a dynamically tilted scale.

Immunomodulatory properties of the lymphatic endothelium in the tumor microenvironment

The tumor microenvironment (TME) is an intricate complex and dynamic structure composed of various cell types, including tumor, stromal and immune cells. Within this complex network, lymphatic endothelial cells (LECs) play a crucial role in regulating immune responses and influencing tumor progression and metastatic dissemination to lymph node and distant organs. Interestingly, LECs possess unique immunomodulatory properties that can either promote or inhibit anti-tumor immune responses. In fact, tumor-associated lymphangiogenesis can facilitate tumor cell dissemination and metastasis supporting immunoevasion, but also, different molecular mechanisms involved in LEC-mediated anti-tumor immunity have been already described. In this context, the crosstalk between cancer cells, LECs and immune cells and how this communication can shape the immune landscape in the TME is gaining increased interest in recent years. In this review, we present a comprehensive and updated report about the immunomodulatory properties of the lymphatic endothelium within the TME, with special focus on primary tumors and tumor-draining lymph nodes. Furthermore, we outline emerging research investigating the potential therapeutic strategies targeting the lymphatic endothelium to enhance anti-tumor immune responses. Understanding the intricate mechanisms involved in LEC-mediated immune modulation in the TME opens up new possibilities for the development of innovative approaches to fight cancer.

Low-Level Laser Therapy Induces Melanoma Tumor Growth by Promoting Angiogenesis

The effects of low-level laser therapy (LLLT) on tumor growth are inconsistent. In this study, we investigated the effects of LLLT on melanoma tumor growth and angiogenesis. C57/BL6 mice were challenged with B16F10 melanoma cells and treated with LLLT for 5 consecutive days; untreated mice were used as controls. Tumor weight, angiogenesis, immunohistochemistry, and protein levels were compared between the treated and untreated mice. In an in vitro experiment, B16F10 cells were treated with LLLT. Proteins were extracted and subjected to Western blot analysis for analyzing signaling pathways. Compared with the findings in the untreated mice, tumor weight substantially increased in the treated mice. Both immunohistochemical and Western blot analyses revealed markedly increased levels of CD31, a biomarker of vascular differentiation, in the LLLT group. In B16F10 cells, LLLT considerably induced the phosphorylation of extracellular signal-regulated kinase (ERK), which, in turn, phosphorylated p38 mitogen-activated protein kinase (MAPK). Furthermore, LLLT induced the expression of vascular endothelial growth factor, but not hypoxia-inducible factor-1α, through the ERK/p38 MAKP signaling pathways. Our findings indicate that LLLT induces melanoma tumor growth by promoting angiogenesis. Therefore, it should be avoided in patients with melanoma.

Reprogramming of sentinel lymph node microenvironment during tumor metastasis

Metastasis is a major cause of death in patients with cancer. The two main routes for cancer cell dissemination are the blood and lymphatic systems. The underlying mechanism of hematogenous metastasis has been well characterized in the past few decades. However, our understanding of the molecular basis of lymphatic metastasis remains at a premature stage. Conceptually, cancer cells invade into lymphatic capillary, passively move to collecting lymphatic vessels, migrate into sentinel lymph node (SLN;, the first lymph node to which cancer cells spread from the primary tumor), and enter the blood circulatory system via the subclavian vein. Before arriving, cancer cells release specific soluble factors to modulate the microenvironment in SLN to establish a beachhead for successful colonization. After colonization, cancer cells inhibit anti-tumor immunity by inducing the recruitment of regulatory T cell and myeloid-derived suppressor cells, suppressing the function of dendritic cell and CD8⁺ T cell, and promoting the release of immunosuppressive cytokines. The development of novel strategies to reverse cancer cell-triggered SLN remodeling may re-activate immunity to reduce beachhead buildup and distant metastasis. In addition to being a microanatomic location for metastasis, the SLN is also an important site for immune modulation. Nanotechnology-based approaches to deliver lymph node-tropic antibodies or drug-conjugated nanoparticles to kill cancer cells on site are a new direction for cancer treatment. Conversely, the induction of stronger immunity by promoting antigen presentation in lymph nodes provides an alternate way to enhance the efficacy of immune checkpoint therapy and cancer vaccine. In this review article, we summarize recent findings on the reprogramming of SLN during lymphatic invasion and discuss the possibility of inhibiting tumor metastasis and eliciting anti-tumor immunity by targeting SLN.

Lymphatic vessels in cancer

The lymphatic system, composed of initial and collecting lymphatic vessels as well as lymph nodes that are present in almost every tissue of the human body, acts as an essential transport system for fluids, biomolecules and cells between peripheral tissues and the central circulation. Consequently, it is required for normal body physiology but is also involved in the pathogenesis of various diseases, most notably cancer. The important role of tumor-associated lymphatic vessels and lymphangiogenesis in the formation of lymph node metastasis has been elucidated during the last two decades, whereas the underlying mechanisms and the relation between lymphatic and peripheral organ dissemination of cancer cells are incompletely understood. Lymphatic vessels are also important for tumor-host communication, relaying molecular information from a primary or metastatic tumor to regional lymph nodes and the circulatory system. Beyond antigen transport, lymphatic endothelial cells, particularly those residing in lymph node sinuses, have recently been recognized as direct regulators of tumor immunity and immunotherapy responsiveness, presenting tumor antigens and expressing several immune-modulatory signals including PD-L1. In this review, we summarize recent discoveries in this rapidly evolving field and highlight strategies and challenges of therapeutic targeting of lymphatic vessels or specific lymphatic functions in cancer patients.

Lymphatics in Tumor Progression and Immunomodulation

The lymphatic system consists of a unidirectional hierarchy of vessels responsible for fluid homeostasis, lipid absorption, and the transport of immune cells and antigens to secondary lymphoid organs. In cancer, lymphatics play complex and heterogenous roles that can promote or inhibit tumor growth. While lymphatic proliferation and remodeling promote tumor dissemination, functional lymphatics are necessary for generating an effective immune response. Recent reports have noted lymphatic-dependent effects on the efficacy of immunotherapy. These findings suggest that the impact of lymphatic vessels on tumor progression is organ- and context-specific and that a greater understanding of the interaction of tumor cells, lymphatics, and the tumor microenvironment can unveil novel therapies.

Dynamic optical coherence tomography shows characteristic alterations of blood vessels in malignant melanoma

BACKGROUND

Dynamic optical coherence tomography (D-OCT) allows in vivo visualization of blood vessels in the skin and in malignant tumours. Vessel patterns in malignant melanoma may be associated with tumour stage.

OBJECTIVE

The aim of this study was to describe blood vessel patterns in melanomas and to correlate them with stage.

METHODS

One hundred fifty-nine malignant melanomas were assessed in a multicentre study. Every tumour was imaged using D-OCT prior to surgery and histologic evaluation. The tumour data such as thickness and ulceration as well as the staging at primary diagnosis and a follow-up of at least 40 months resulted in a stage classification. The vessel patterns were assessed according to predefined categories, compared with healthy adjacent skin, and correlated to stage.

RESULTS

Melanomas contained more blood vessels in different patterns compared with healthy adjacent skin. In particular, irregular vascular shapes such as blobs, coils, curves and serpiginous vessels were more common in melanomas. In addition, these patterns were significantly more often found in high-risk and metastatic melanomas than in low-risk lesions.

CONCLUSION

In melanomas, the density of the blood vessels is increased, and irregular vascular patterns are more frequent. At higher stages, especially in metastatic melanomas, these atypical vessels are significantly more common.

Predictors of Nonsentinel Lymph Node Metastasis in Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Although completion lymph node dissection (CLND) is not routinely performed for a positive sentinel lymph node (SLN) anymore, adjuvant therapy depends on the risk factors available from SLN biopsy, including the risk of nonsentinel node metastases (NSNM). A systematic review and meta-analysis was performed in an attempt to identify risk factors that could be used to predict the risk of NSNM.

MATERIALS AND METHODS

Medline, Web of Science, Embase, and Cochrane were searched for articles discussing predictive factors for NSNM. PRISMA guidelines were followed, and RevMan software was used to calculate pooled odds ratios (OR) using the Mantel-Haenszel test.

RESULTS

Fifty publications were suitable for additional analysis. The clinical and primary tumor factors that were consistently identified as risk factors for NSNMs were: age >50, T stage 3 or 4, Clark level IV/V, ulceration, microsatellitosis, lymphovascular invasion, nodular histology, and extremity versus trunk primary tumor location. SLN factors that predicted NSNMs were >1 positive SLN, SLN micrometastatic tumor burden, diameter >2 mm, extracapsular extension, nonsubcapsular location (Dewar), and Rotterdam > 1 mm or ≥ 0.1 mm.

CONCLUSIONS

The findings in this study support that many clinical and pathologic risk factors that can be assessed with SLN biopsy alone can be used to predict the risk of NSNMs. The factors identified in this review should be evaluated in clinical prediction models to predict the risk of NSNMS, a prediction that may be used to select patients for adjuvant therapy in high-risk melanoma.

Endothelial Progenitors in the Tumor Microenvironment

Tumor vascularization refers to the formation of new blood vessels within a tumor and is considered one of the hallmarks of cancer. Tumor vessels supply the tumor with oxygen and nutrients, required to sustain tumor growth and progression, and provide a gateway for tumor metastasis through the blood or lymphatic vasculature. Blood vessels display an angiocrine capacity of supporting the survival and proliferation of tumor cells through the production of growth factors and cytokines. Although tumor vasculature plays an essential role in sustaining tumor growth, it represents at the same time an essential way to deliver drugs and immune cells to the tumor. However, tumor vasculature exhibits many morphological and functional abnormalities, thus resulting in the formation of hypoxic areas within tumors, believed to represent a mechanism to maintain tumor cells in an invasive state.Tumors are vascularized through a variety of modalities, mainly represented by angiogenesis, where VEGF and other members of the VEGF family play a key role. This has represented the basis for the development of anti-VEGF blocking agents and their use in cancer therapy: however, these agents failed to induce significant therapeutic effects.Much less is known about the cellular origin of vessel network in tumors. Various cell types may contribute to tumor vasculature in different tumors or in the same tumor, such as mature endothelial cells, endothelial progenitor cells (EPCs), or the same tumor cells through a process of transdifferentiation. Early studies have suggested a role for bone marrow-derived EPCs; these cells do not are true EPCs but myeloid progenitors differentiating into monocytic cells, exerting a proangiogenic effect through a paracrine mechanism. More recent studies have shown the existence of tissue-resident endothelial vascular progenitors (EVPs) present at the level of vessel endothelium and their possible involvement as cells of origin of tumor vasculature.

Diagnostic value of NSE factor combined with ultrasound hemodynamic indexes in cervical lymph node metastasis of lung cancer

Value of neuron-specific enolase (NSE) factor combined with ultrasound hemodynamic parameters in the diagnosis of cervical lymph node metastasis of lung cancer was explored. The clinical data of 85 patients with lung cancer, admitted to Qingdao Municipal Hospital (Group) from January 2015 to December 2016, were retrospectively analyzed. According to the results of pathological examination, 47 patients with cervical lymph node metastasis were enrolled in the metastatic group and 38 patients without lymph node metastasis were enrolled in the non-metastatic group. The expression level of NSE in serum and the hemodynamic indicators of blood flow resistance index (RI) and pulsatility index (PI) were compared between the two groups. ROC curve analysis was used to analyze the diagnostic efficacy of NSE, RI, PI, and their combination in lymph node metastasis of lung cancer. The NSE, RI and PI indexes in the metastatic group were significantly higher than those in the non-metastatic group (P<0.05). The sensitivity and specificity of NSE in the diagnosis of cervical lymph node metastasis of lung cancer were 73.68 and 72.34%, respectively; the sensitivity and specificity of RI were 78.95 and 80.85%, respectively; the sensitivity and specificity of PI were 81.58 and 68.09%, respectively. Also, the sensitivity and specificity of NSE combined with RI were 89.47 and 61.70%, respectively, and the diagnostic AUC was 0.881. The sensitivity and specificity of NSE combined with PI were 92.11 and 74.47%, respectively, and the diagnostic AUC was 0.905. NSE, RI, and PI have certain diagnostic value for cervical lymph node metastasis of lung cancer, however, the combined diagnosis is more valuable, and can be used as the auxiliary diagnosis of cervical lymph node metastasis of lung cancer.

Mechanisms of Tumor-Induced Lymphovascular Niche Formation in Draining Lymph Nodes

Enlargement of the lymphatic vascular network in tumor-draining lymph nodes (LNs) often precedes LN metastasis, likely providing a lymphovascular niche for tumor cells. We investigated morphological and molecular changes associated with the lymphatic remodeling process, using the 4T1 breast cancer and B16F10 melanoma models. Lymphatic expansion in tumor-draining LNs is mediated by sprouting and proliferation of lymphatic endothelial cells (LECs) as early as 4 days after tumor implantation. RNA sequencing revealed an altered transcriptional profile of LECs from tumor-draining compared to naive LNs with similar changes in both tumor models. Integrin αIIb is upregulated in LECs of tumor-draining LNs and mediates LEC adhesion to fibrinogen in vitro. LEC-associated fibrinogen was also detected in LNs in vivo, suggesting a role of integrin αIIb in lymphatic remodeling. Together, our results identify specific responses of LN LECs to tumor stimuli and provide insights into the mechanisms of lymphovascular niche formation in tumor-draining LNs.

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Lymph node lymphatic endothelial cells (LN LECs) dramatically react to tumor stimuli

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Cell adhesion molecules are among the strongest differentially regulated genes

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Itga2b is upregulated and associated with fibrinogen in tumor-draining LN LECs

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Itga2b mediates adhesion of LN LECs to fibrinogen

Prognostic value of uPAR expression and angiogenesis in primary and metastatic melanoma

Angiogenesis is important for the progression of cutaneous melanoma. Here, we analyzed the prognostic impact of the angiogenic factor urokinase plasminogen activator resecptor (uPAR), vascular proliferation index (VPI) and tumor necrosis as a measure of hypoxia in a patient series of nodular melanomas (n = 255) and matched loco-regional metastases (n = 78). Expression of uPAR was determined by immunohistochemistry and VPI was assessed by dual immunohistochemistry using Factor-VIII/Ki67 staining. Necrosis was recorded based on HE-slides. As novel findings, high uPAR expression and high VPI were associated with each other, and with increased tumor thickness, presence of tumor necrosis, tumor ulceration, increased mitotic count and reduced cancer specific survival in primary melanoma. In matched cases, VPI was decreased in metastases, whereas the frequency of necrosis was increased. Our findings demonstrate for the first time the impact on melanoma specific survival of uPAR expression and VPI in primary tumors, and of increased necrosis as an indicator of tumor hypoxia in loco-regional metastases. These findings support the importance of tumor angiogenesis in melanoma aggressiveness, and suggest uPAR as an indicator of vascular proliferation and a potential biomarker in melanoma.

Sentinel Lymph Node Characterization with a Dual-Targeted Molecular Ultrasound Contrast Agent

PURPOSE

The purpose of this study was to assess the performance of molecular ultrasound with dual-targeted microbubbles to detect metastatic disease in the sentinel lymph nodes (SLNs) in swine model of naturally occurring melanoma. The SLN is the first lymph node in the lymphatic chain draining primary tumor, and early detection of metastatic SLN involvement is critical in the appropriate management of melanoma.

PROCEDURE

Nine Sinclair swine (weight 3-7 kg; Sinclair BioResources, Columbia, MO, USA) with naturally occurring melanoma were examined. Siemens S3000 scanner with a 9L4 probe was used for imaging (Siemens Healthineers, Mountain View, CA). Dual-targeted contrast agent was created using Targestar SA microbubbles (Targeson, San Diego, CA, USA) labeled with α_νβ₃-integrin and P-selectin antibodies. Targestar SA microbubbles labeled with IgG-labeled were used as control. First, peritumoral injection of Sonazoid contrast agent (GE Healthcare, Oslo, Norway) was performed to detect SLNs. After that, dual-targeted and IGG control Targestar SA microbubbles were injected intravenously with a 30-min interval between injections. Labeled Targestar SA microbubbles were allowed to circulate for 4 min to enable binding. After that, two sets of image clips were acquired several seconds before and after a high-power destruction sequence. The mean intensity difference pre- to post-bubble destruction within the region of interest placed over SLN was calculated as a relative measure of targeted microbubble contrast agent retention. This process was repeated for non-SLNs as controls. All lymph nodes evaluated on imaging were surgically removed and histologically examined for presence of metastatic involvement.

RESULTS

A total of 43 lymph nodes (25 SLNs and 18 non-SLNs) were included in the analysis with 18 SLNs demonstrating metastatic involvement greater than 5 % on histology. All non-SLNs were benign. The mean intensity (± SD) of the dual-targeted microbubbles for metastatic SLNs was significantly higher than that of benign LNs (18.05 ± 19.11 vs. 3.30 ± 6.65 AU; p = 0.0008), while IgG-labeled control microbubbles demonstrated no difference in retained contrast intensity between metastatic and benign lymph nodes (0.39 ± 1.14 vs. 0.03 ± 0.24 AU; p = 0.14).

CONCLUSIONS

The results indicate that dual-targeted microbubbles labeled with P-selectin and α_νβ₃-integrin antibodies may aid in detecting metastatic involvement in SLNs of melanoma.

Review of diagnostic, prognostic, and predictive biomarkers in melanoma

Melanoma is an aggressive cutaneous malignancy with rapidly rising incidence. Diagnosis of controversial melanocytic lesions, correct prognostication of patients, selection of appropriate adjuvant and systemic therapies, and prediction of response to a given therapy remain very real challenges. Despite these challenges, multiple high throughput, nucleic-acid based biomarkers have been developed that can be assayed from histologic tissue specimens. FISH, CGH, Decision-Dx, and other multi-marker assays have been combined to improve overall predictability. This review discusses some of the most promising nucleic acid based assays that can be obtained from tissue specimens to assist with diagnosis, prognostication, and prediction of treatment response.

Microvessel Density in Patients with Cutaneous Melanoma: An Up-to-Date Systematic Review and Meta-Analysis

Background

We conducted a meta-analysis, in order to appraise the effect of microvessel density (MVD) on the survival of patients with cutaneous melanoma.

Methods

This study was conducted according to the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. A systematic literature search in electronic databases (MEDLINE, Web of Science, and Cochrane Central Register of Controlled Clinical Trials) was performed. Fixed Effects or Random Effects model was used, based on the Cochran Q test.

Results

In total 9 studies (903 patients) were included. Pooled HR for overall survival (OS) and disease-free survival (DFS) were 2.62 (95% CI: 0.71–9.60, p = 0.15) and 2.64 (95% CI: 0.82–8.47, p = 0.10), respectively. Odds ratios of overall survival between high and low MVD groups, at 12 (1.45, 95% CI: 0.16–13.24), 36 (2.93, 95% CI: 0.63–13.59), and 60 (4.09, 95% CI: 0.85–19.77) months did not reach statistical significance. Significant superiority of low MVD group, in terms of DFS, at all time intervals (OR: 4.69, p < 0.0001; OR: 2.18, p = 0.004; OR: 7.46, p = 0.01, resp.) was documented.

Discussion

MVD does not affect the HR of OS and DFS. A strong correlation with DFS rates at 12, 36, and 60 months was recorded.

Metastatic and non-metastatic lymph nodes: quantification and different distribution of iodine uptake assessed by dual-energy CT

OBJECTIVES

To evaluate quantification of iodine uptake in metastatic and non-metastatic lymph nodes (LNs) by dual-energy CT (DECT) and to assess if the distribution of iodine within LNs at DECT correlates with the pathological structure.

METHODS

Ninety LNs from 37 patients (23 with lung and 14 with gynaecological malignancies) were retrospectively selected. Information of LNs sent for statistical analysis included Hounsfield units (HU) at different energy levels; decomposition material densities fat-iodine, iodine-fat, iodine-water, water-iodine. Statistical analysis included evaluation of interobserver variability, material decomposition densities and spatial HU distribution within LNs.

RESULTS

Interobserver agreement was excellent. There was a significant difference in iodine-fat and iodine-water decompositions comparing metastatic and non-metastatic LNs (p < 0.001); fat-iodine and water-iodine did not show significant differences. HU distribution showed a significant gradient from centre to periphery within non-metastatic LNs that was significant up to 20-30% from the centre, whereas metastatic LNs showed a more homogeneous distribution of HU, with no significant gradient.

CONCLUSIONS

DECT demonstrated a lower iodine uptake in metastatic compared to non-metastatic LNs. Moreover, the internal iodine distribution showed an evident gradient of iodine distribution from centre to periphery in non-metastatic LNs, and a more homogeneous distribution within metastatic LNs, which corresponded to the pathological structure.

KEY POINTS

• This study demonstrated a lower iodine uptake in metastatic than non-metastatic LNs. • Internal distribution of HU was different between metastatic and non-metastatic lymph nodes. • The intranodal iodine distribution disclosed a remarkable correlation with the histological LN structure.