Intratumoral Lymphatics and Lymphatic Vessel Invasion Detected by D2‐40 Are Essential for Lymph Node Metastasis in Bladder Transitional Cell Carcinoma

Bladder cancer is frequently associated with regional lymph node metastasis at the time of diagnosis or after initial treatment, and lymph node metastasis is crucial for clinical therapeutic strategies. Lymphangiogenesis, detected by antibodies specific for lymphatic endothelial cells, is correlated with cancer spread, but the mechanisms that underlie lymphatic spread and the role of lymphangiogenesis in cancer metastasis has been less clear. The aim of this study was to investigate the association of vascular endothelial growth factor (VEGF)‐D expression, intratumoral lymphatics, and lymphatic invasion associated with lymph node metastasis as well as the prognostic analysis in patients with bladder transitional cell carcinoma (TCC). The VEGF‐D expression was evaluated by immunohistochemistry in 72 specimens, and tumoral lymphatic vessels were measured by D2‐40. Counts of lymph vessels were taken in intratumoral and peritumoral areas. Survival analyses and their independent roles were investigated using univariate and multivariate analysis models. The high expression of VEGF‐D was closely associated with the intratumoral lymphatic vessels, tumoral lymphatic invasion, and lymph node metastasis as well as a shorter overall survival. Higher lymphatic vessel density, intratumoral lymphatics, and lymphatic invasion showed a significant association with lymph node metastasis. Univariate analysis indicated that VEGF‐D, intratumoral lymphatics, and lymphatic invasion were associated with overall survival, but they were not independent prognostic factors for bladder TCC in multivariate analysis. We conclude that VEGF‐D plays an essential role in tumoral lymphangiogenesis. Intratumoral lymphatics and lymphatic invasion are important predictive factors of pelvic lymph node metastasis in patients with bladder cancer. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

Expression of VEGF‐C and VEGF‐D as Significant Markers for Assessment of Lymphangiogenesis and Lymph Node Metastasis in Non‐Small Cell Lung Cancer

Vascular endothelial growth factor (VEGF)‐C and VEGF‐D induce lymphangiogenesis through activation of VEGF receptor 3 (VEGFR‐3) and have been implicated in tumor spread to the lymphatic system. Lymph node dissemination critically determines clinical outcome and therapeutic options of patients with non‐small cell lung cancer (NSCLC). However, the relationship of VEGF‐C, VEGF‐D, and lymph node metastasis in cancers, including NSCLC, is still controversial. To evaluate the relationship between lymphangiogenesis and lymph node metastasis, the expression of VEGF‐C and VEGF‐D in NSCLC tumors were detected by immunohistochemistry and quantitative real‐time polymerase chain reaction (QRT‐PCR). QRT‐PCR revealed that in marginal region VEGF‐C and VEGF‐D mRNA was significantly higher than in tumor center, and VEGF‐D mRNA was also higher than that in peritumoral lung tissue. Immunohistochemically, we observed the same heterogeneous expression of VEGF‐C and VEGF‐D proteins. The group with high expression of VEGF‐C and VEGF‐D in marginal region had a higher incidence of lymph node metastasis compared with the group with low expression. Furthermore, the group with high expression of VEGF‐D in marginal region had a higher incidence of lymphatic invasion. The group with high peritumoral lymphatic vessel density (LVD) had higher expression of VEGF‐C and VEGF‐D mRNA compared with the group with low peritumoral LVD. Our studies suggested that the expression of VEGF‐C and VEGF‐D at invasive edge was significantly associated with lymph node metastasis or lymphatic invasion in patients with NSCLC and may be involved in regulation of lymphangiogenesis and lymph node metastasis in NSCLC. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

Vascular Endothelial Growth Factor D and Intratumoral Lymphatics as Independent Prognostic Factors in Epithelial Ovarian Carcinoma

Lymph node metastasis is an important prognostic indicator for disease progression and is crucial for therapeutic strategies of epithelial ovarian carcinoma. Vascular endothelial growth factor (VEGF)‐D has been confirmed to have potent lymphangiogenic function in experimental models, but the role in the progression of human ovarian carcinoma remains presently controversial. The purpose of this study was to investigate the prognostic significance of VEGF‐D and the presence of intratumoral lymphatics in patients with epithelial ovarian carcinoma. The VEGF‐D expression was evaluated by immunohistochemistry in 78 specimens of epithelial ovarian carcinoma and tumoral lymphatic vessels were measured by D2‐40. The expression of VEGF‐D protein was detected in the cytoplasm of the tumor cells and in stroma occasionally. The high expression of VEGF‐D was closely associated with the FIGO stage, intratumoral lymphatic vessels, tumoral lymphatic invasion, and lymph node metastasis as well as a shorter overall survival. Univariate and multivariate analysis indicated that VEGF‐D, intratumoral lymphatics, and lymphatic invasion were independent prognostic factors for overall survival and disease‐free survival in patients with epithelial ovarian carcinoma. We conclude that VEGF‐D plays an essential role in tumoral lymphangiogenesis and lymphatic spread, VEGF‐D expression, and the intratumoral lymphatics may be clinically useful indicators for prognostic evaluation in patients with epithelial ovarian carcinoma. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.     

Tumour necrosis factor superfamily member 15 (Tnfsf15) facilitates lymphangiogenesis via up‐regulation of Vegfr3 gene expression in lymphatic endothelial cells

Lymphangiogenesis is essential in embryonic development but is rare in adults. It occurs, however, in many disease conditions including cancers. Vascular endothelial growth factor‐C/D (VEGF‐C/D) and VEGF receptor‐3 (Vegfr3) play a critical role in the regulation of lymphangiogenesis. We investigated how the VEGF‐C/Vegfr3 signalling system is regulated by tumour necrosis factor superfamily member 15 (Tnfsf15), an endothelium‐derived cytokine. We report here that Tnfsf15, which is known to induce apoptosis in vascular endothelial cells, can promote lymphatic endothelial cell (LEC) growth and migration, stimulate lymphangiogenesis, and facilitate lymphatic circulation. Treatment of mouse LECs with Tnfsf15 results in up‐regulation of Vegfr3 expression; this can be inhibited by gene silencing of death domain‐containing receptor‐3 (DR3; Tnfrsf25), a cell surface receptor for Tnfsf15, with siRNA, or by blocking Tnfsf15–DR3 interaction with a Tnfsf15 neutralizing antibody, 4‐3H. Additionally, Tnfsf15/DR3 signalling pathways in LECs include activation of NF‐κB. Tnfsf15‐overexpressing transgenic mice exhibit a marked enhancement of lymph drainage; this is confirmed by treatment of wild‐type mice with intraperitoneal injection of recombinant Tnfsf15. Moreover, systemic treatment of pregnant Tnfsf15 transgenic mice with 4‐3H leads to inhibition of embryonic lymphangiogenesis. Our data indicate that Tnfsf15, a cytokine produced largely by endothelial cells, facilitates lymphangiogenesis by up‐regulating Vegfr3 gene expression in LECs, contributing to the maintenance of the homeostasis of the circulatory system. This finding also suggests that Tnfsf15 may be of potential value as a therapeutic tool for the treatment of lymphoedema. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Lentivirus‐Mediated Small Interfering RNA Targeting VEGF‐C Inhibited Tumor Lymphangiogenesis and Growth in Breast Carcinoma

Lymph node metastasis is a major prognostic factor for patients with breast cancer. The activation of vascular endothelial growth factor (VEGF)‐C plays a key role in lymph node metastasis through promoting lymphangiogenesis. Thus, we attempted to elucidate whether small interfering RNAs (siRNA) targeting VEGF‐C could suppress lymphangiogenesis and lymph node metastasis in vivo. A lentivirus‐based VEGF‐C siRNA vector was infected into breast cancer cells and a xenograft model. The expression of VEGF‐C mRNA and protein were quantified by quantitative real‐time polymerase chain reaction (QRT‐PCR), immunohistochemistry, and western blot analysis. The effect of VEGF‐C siRNA on breast cancer cells was investigated by an invasion assay. Lymphangiogenesis was analyzed with anti‐LYVE‐1 and anti‐D2‐40 by immunohistochemical analysis. Lentivirus‐mediated VEGF‐C siRNA stably reduced VEGF‐C mRNA and protein expression. VEGF‐C siRNA inhibited the invasive ability of breast cancer cells in vitro. Five weeks after intratumoral injection, the tumor volume was significantly smaller in the VEGF‐C siRNA group than in the control scramble siRNA group in the MDA‐MB‐231 cell xenograft model. The numbers of LYVE‐1 and D2‐40 positive vessels per microscopic field were significantly decreased in the VEGF‐C siRNA group, which indicates that VEGF‐C siRNA inhibited lymphangiogenesis. Moreover, lymph node metastasis was significantly suppressed by VEGF‐C siRNA in vivo. In conclusion, these results indicate that lentivirus‐mediated VEGF‐C siRNA offers a new approach for therapeutic intervention to prevent tumor growth and lymphatic metastasis of breast cancer. Anat Rec, 292:633–639, 2009. © 2009 Wiley‐Liss, Inc.     

Inhibition of Cyclooxygenase‐2 Suppresses Lymph Node Metastasis via VEGF‐C

Most experimental work addressing cyclooxygenase‐2 (COX‐2) inhibitor has focused on suppressing hematogenic spread. Little is known about the mechanism by which this inhibitor can also block lymphatic metastasis. Here, the effects of COX‐2 inhibitor on vascular endothelial growth factor‐C (VEGF‐C) expression, lymphangiogenesis and lymph node metastasis were investigated. Utilizing the highly metastatic human lung adenocarcinoma cell line Anip973 and its parental line AGZY83‐a, which has a low metastatic capacity, we found elevated VEGF‐C and COX‐2 immunoreactivity in Anip973 cells compared with AGZY83‐a cells. Celecoxib down‐regulated expression of VEGF‐C mRNA and protein in Anip973 cells while PGE₂ up‐regulated expression of VEGF‐C mRNA and protein in AGZY83‐a cells in a concentration‐dependent manner. The expression of COX‐2 and VEGF‐C was significantly increased in xenografted Anip973 tumors compared with AGZY83‐a tumors. The Anip973 tumors showed more lymphatic vessels and lymph node metastasis than the AGZY83‐a tumors. In vivo, celecoxib decreased VEGF‐C expression in Anip973 tumor‐treated mice to a similar level to that in the AGZY83‐a tumor‐treated mice. Consistent with this decrease in VEGF‐C expression, the density of lymphatic vessels and lymph node metastasis in Anip973 tumor‐treated mice were suppressed to approximately that found in the AGZY83‐a tumor‐treated ones. Taken together, our results suggest that the differential expression of COX‐2 and VEGF‐C might help explain the different metastasis phenotype of lung adenocarcinoma cancer, and that COX‐2 inhibitor mediates VEGF‐C to block lymphangiogenesis and lymph node metastasis. Thus, COX‐2 may be a potential therapeutic target for blocking lymph node metastasis in lung adenocarcinoma. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.     

Lymphangiogenesis and Prognostic Significance of Vascular Endothelial Growth Factor C in Gastro‐oesophageal Junction Adenocarcinoma

Vascular endothelial growth factor C (VEGF‐C) is a crucial regulator of the development of lymphatic vessels and is involved in the lymph node metastasis of cancer. The levels of VEGF‐C expression and lymphatic vessel density (LVD) in 128 gastro‐oesophageal junction adenocarcinoma (GEJA) tissues were examined by immunohistochemistry and analysed for their association with clinicopathological features and disease‐free survival. We found that 75.0% of tumour samples displayed strong immunoreactivity to VEGF‐C. The levels of VEGF‐C expression in the tumour tissues were associated with the stages of the clinical tumours and the lymph node metastasis status, but not with the age, gender and the size and type of tumours in the cohort. Similarly, LVD, as evaluated by anti‐D2‐40 staining, was also associated with the clinical stages of GEJA. The values of LVD were positively correlated with the levels of VEGF‐C expression in these samples (r = 0.3760, P = 0.0001). High levels of VEGF‐C expression and high values of LVD were associated with shorter periods of disease‐free survival (DFS) in patients with GEJA (P < 0.001). In addition, GEJA at N1 and N2 stages, at T4 stage, chemotherapy after surgery, high levels of VEGF‐C expression and lower marginal resection were independent factors for the prognosis of DFS in patients with GEJA. Our data indicate that VEGF‐C may promote the lymphangiogenesis and lymphatic metastasis of GEJA and that VEGF‐C may be a valuable biomarker for the diagnosis of lymphatic metastasis and a prognostic factor of the survival of patients with GEJA.     

VEGF‐D promotes pulmonary oedema in hyperoxic acute lung injury

Leakage of fluid from blood vessels, leading to oedema, is a key feature of many diseases including hyperoxic acute lung injury (HALI), which can occur when patients are ventilated with high concentrations of oxygen (hyperoxia). The molecular mechanisms driving vascular leak and oedema in HALI are poorly understood. VEGF‐D is a protein that promotes blood vessel leak and oedema when overexpressed in tissues, but the role of endogenous VEGF‐D in pathological oedema was unknown. To address these issues, we exposed Vegfd‐deficient mice to hyperoxia. The resulting pulmonary oedema in Vegfd‐deficient mice was substantially reduced compared to wild‐type, as was the protein content of bronchoalveolar lavage fluid, consistent with reduced vascular leak. Vegf‐d and its receptor Vegfr‐3 were more highly expressed in lungs of hyperoxic, versus normoxic, wild‐type mice, indicating that components of the Vegf‐d signalling pathway are up‐regulated in hyperoxia. Importantly, VEGF‐D and its receptors were co‐localized on blood vessels in clinical samples of human lungs exposed to hyperoxia; hence, VEGF‐D may act directly on blood vessels to promote fluid leak. Our studies show that Vegf‐d promotes oedema in response to hyperoxia in mice and support the hypothesis that VEGF‐D signalling promotes vascular leak in human HALI. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Endostatin inhibits tumour lymphangiogenesis and lymphatic metastasis via cell surface nucleolin on lymphangiogenic endothelial cells

Endostatin has potent anti‐endothelial and anti‐angiogenic functions. Endostatin was reported to reduce lymphangiogenesis by down‐regulating the level of VEGF‐C in tumour tissues. However, there is little evidence for the direct function of endostatin on lymphangiogenic endothelial cells and lymphangiogenic vessels. Here, we report that cell surface nucleolin, which was reported as an endostatin receptor mediating its anti‐angiogenic and anti‐tumour functions, is also selectively expressed on the cell surface of lymphangiogenic endothelial cells both in vitro and in vivo. Treatment of primary mouse lymphatic endothelial cells (mLECs) by endostatin inhibits mLEC migration, tubule formation, and activation of the Erk pathway in mLECs, while neutralization of cell surface nucleolin or nucleolin knockdown results in loss of the anti‐lymphatic endothelial activities of endostatin. Also, anti‐nucleolin antibody or lentivirus delivered nucleolin siRNA abolishes the anti‐lymphangiogenic function of endostatin in the Matrigel plug assay. Endostatin remarkably inhibits tumour‐associated lymphangiogenesis, leading to reduced lymphatic metastasis. Systemic blockade of nucleolin notably abolishes the anti‐lymphangiogenic and anti‐lymphatic metastatic functions of endostatin. Importantly, endostatin does not affect quiescent lymphatics in normal organs, which is consistent with the lack of expression of cell surface nucleolin in quiescent lymphatics. Taken together, our results demonstrate that endostatin directly acts on lymphangiogenic endothelial cells via cell surface nucleolin, which provides a novel mechanism for the inhibition of tumour lymphangiogenesis and lymphatic metastasis by endostatin. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Lymphangiogenesis in gastric carcinoma correlates with prognosis

Lymphatic metastasis is an important way that gastric carcinomas can spread. However, little is known about the mechanisms of lymphangiogenesis and its clinical significance in gastric carcinomas. In the present study, lymphatic vessel density (LVD), VEGF‐C expression, and proliferative activity of lymphatic endothelium were determined in human gastric carcinomas and xenografts of gastric cancer cells in nude mice. The development of lymphangiogenesis and its correlation with patient prognosis were investigated. The results showed that lymphatic vessels were observed mainly in peripheral tumour tissue with significantly (p < 0.05) higher P‐LVD (peri‐tumoural‐LVD) than I‐LVD (intra‐tumoural‐LVD). The expression of VEGF‐C was heterogeneous within tumours, with a significantly higher expression (immunostaining score) at the margin than at the tumour centre (p < 0.05). A significant correlation was found between VEGF‐C expression at the margin (but not at the centre) and P‐LVD (r = 0.72, p < 0.01). High proliferative activity of lymphatic endothelium was also observed in the peripheral tissues, with a significant correlation between proliferative activity of lymphatic endothelium and VEGF‐C expression (p < 0.05). These data imply that the increased lymphatics may have been newly formed following stimulation by VEGF‐C. High VEGF‐C expression at the margin of gastric carcinomas could induce lymphangiogenesis in the peri‐tumoural stroma and contribute to the increased P‐LVD. The data from mice tumour xenografts also suggested that VEGF‐C produced from the transplanted gastric carcinoma cells could induce lymphangiogenesis around them. In patients, VEGF‐C expression at tumour margins was associated with nodal metastasis, lymphatic vessel invasion, poor recurrence‐free survival, and poor overall survival, and could serve as an independent predictor for patients with gastric carcinoma. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Murine Notch1 is required for lymphatic vascular morphogenesis during development

BACKGROUND: The transmembrane receptor Notch1 is a critical regulator of arterial differentiation and blood vessel sprouting. Recent evidence shows that functional blockade of Notch1 and its ligand, Dll4, leads to postnatal lymphatic defects in mice. However, the precise role of the Notch signaling pathway in lymphatic vessel development has yet to be defined. Here we show the developmental role of Notch1 in lymphatic vascular morphogenesis by analyzing lymphatic endothelial cell (LEC)‐specific conditional Notch1 knockout mice crossed with an inducible Prox1CreER^T2 driver. RESULTS: LEC‐specific Notch1 mutant embryos exhibited enlarged lymphatic vessels. The phenotype of lymphatic overgrowth accords with increased LEC sprouting from the lymph sacs and increased filopodia formation. Furthermore, cell death was significantly reduced in Notch1‐mutant LECs, whereas proliferation was increased. RNA‐seq analysis revealed that expression of cytokine/chemokine signaling molecules was upregulated in Notch1‐mutant LECs isolated from E15.5 dorsal skin, whereas VEGFR3, VEGFR2, VEGFC, and Gja4 (Connexin 37) were downregulated. CONCLUSIONS: The lymphatic phenotype of LEC‐specific conditional Notch1 mouse mutants indicates that Notch activity in LECs controls lymphatic sprouting and growth during development. These results provide evidence that similar to postnatal and pathological lymphatic vessel formation, the Notch signaling pathway plays a role in inhibiting developmental lymphangiogenesis. Developmental Dynamics 243:957–964, 2014. © 2014 Wiley Periodicals, Inc.     

血管内皮生长因子C及其受体3在非小细胞肺癌组织中的表达及意义

目的　探讨血管内皮生长因子C(VEGF C)和受体 (VEGFR) 3在人非小细胞肺癌(NSCLC)组织中的表达及其与微血管、微淋巴管形成、淋巴转移、预后之间的关系。方法　对 76例人NSCLC及相应癌旁组织行VEGF C、VEGFR 3及CD34免疫组织化学染色链霉素抗生物素蛋白 过氧化物酶 (SP)法检测 ,进行淋巴管密度计数、微血管密度 (MVD)计数 ,并结合临床和病理资料进行分析。结果　NSCLC中 ,VEGF C的表达与肺癌分化程度负相关 (P =0 0 0 9)。VEGF C和VEGFR 3的表达水平与淋巴结转移呈正相关 (分别P =0 0 0 8,P =0 0 13) ,与淋巴浸润呈正相关 (分别P =0 0 2 7,P =0 0 2 0 )。VEGF C的表达与VEGFR 3在肺癌细胞中的表达呈正相关 (P =0 0 0 9)。VEGF C与淋巴管密度 (P =0 0 0 6 )、MVD(P =0 0 4 6 )呈正相关。淋巴管密度与淋巴结转移 (P =0 0 10 )、淋巴浸润 (P =0 0 19)、TNM分期 (P =0 0 15 )呈正相关 ,MVD与血行转移 (P <0 0 0 1)、TNM分期 (P <0 0 0 1)呈正相关。VEGF C阳性表达与生存时间、5年生存率呈负相关 (P <0 0 0 1)。结论　NSCLC中 ,VEGF C通过自分泌方式作用于受体VEGFR 3,促进肺癌组织生长 ,抑制分化。VEGF C促使肺癌内淋巴管形成 ,促进肺癌淋巴结转移。VEGF C和VEGFR 3表达增高、淋巴管密度增加     

Integrin α4 Induces Lymphangiogenesis and Metastasis via Upregulation of VEGF‐C in Human Colon Cancer

Vascular endothelial growth factor‐C (VEGF‐C) is a key regulator in lymphangiogenesis, and is overexpressed in various malignancies. Integrin α4β1, a new member of the VEGF‐C/VEGF receptor pathway, was found to be overexpressed in melanoma tumors. However, little is known regarding the potential role of integrin α4β1 in lymphangiogenesis and other solid tumors. The aim of this study was to investigate the expression patterns of integrin α4 and VEGF‐C in relation to lymphangiogenesis and clinicopathological parameters in human colon cancer. The expression of integrin α4, VEGF‐C, and VEGFR‐3 was assessed in 71 human colon cancer tissues and 30 paracancerous normal tissues by immunohistochemical staining. Lymphatic microvessel density (LMVD) was measured after D2‐40‐labeling, and the correlations among different factors were statistically analyzed. The expression of integrin α4, VEGF‐C, VEGFR‐3, and LMVD was higher in colon cancer tissues compared with the normal paracancerous colon tissues. There was a positive correlation between the expression of integrin α4 and VEGF‐C. Integrin α4 and VEGF‐C were significantly associated with the clinicopathological parameters (LMVD, Duke's stage, and lymph node metastasis). Kaplan–Meier analyses indicated that patients with high integrin α4 or VEGF‐C expression had significantly shorter overall survival and tumor‐free survival time. Multivariate analyses suggested that integrin α4 and VEGF‐C may serve as independent prognostic factors for human colon cancer. Both integrin α4 and VEGF‐C are involved in lymphangiogenesis and lymphatic metastasis. Our results demonstrated that integrin α4 is a novel prognostic indicator for human colon cancer. Anat Rec, 299:741–747, 2016. © 2016 Wiley Periodicals, Inc.     

Angiogenic and lymphangiogenic microvessel density in breast carcinoma: correlation with clinicopathologic parameters and VEGF-family gene expression.

Angiogenesis and lymphangiogenesis are essential for breast cancer progression and are regulated by vascular endothelial growth factors (VEGF). To determine clinical and molecular correlates of these processes, we measured blood and lymphatic vascular microvessel density in 29 invasive carcinomas (22 ductal, six lobular, one papillary), using the vascular marker CD31 and the novel lymphatic marker D2-40. Microvessel density was assessed microscopically and by image cytometry, and was compared with tumor histology, grade, stage, lymph node metastasis, hormone receptors, HER2/neu status, and expression of VEGF, VEGF-C and VEGF-D by immunohistochemistry or quantitative RT-PCR. Strong correlation was observed between visual and image cytometric microvessel density using D2-40 but not CD31 (P=0.016 and 0.1521, respectively). Image cytometric CD31 microvessel density correlated with tumor size, grade, stage and lymph node metastasis (P=0.0001, 0.0107, 0.0035 and 0.0395, respectively). D2-40 microvessel density correlated with tumor stage (P=0.0123 by image cytometry) and lymph node metastasis (P=0.0558 by microscopy). Immunohistochemical VEGF signal in peritumoral blood vessels correlated with image cytometric CD31 and D2-40 microvessel density (P=0.022 and 0.0012, respectively), consistent with the role of VEGF in blood and lymphatic vascular growth. Intratumoral VEGF-C and VEGF-D expression by quantitative RT-PCR correlated with D2-40 (P=0.0291 by image cytometry) but not with CD31 microvessel density, which could suggest a selective role of VEGF-C and VEGF-D in lymphangiogenesis. CD31 and D2-40 microvessel density correlated significantly with several prognostic factors, including lymph node metastasis. Thus, measurements of angiogenesis and lymphangiogenesis may have utility for breast cancer pathology, particularly for estimation of metastatic risk.     

Lymphangiogenesis in regional lymph nodes predicts nodal recurrence in pathological N0 squamous cell carcinoma of the tongue

Hirota K, Wakisaka N, Sawada‐Kitamura S, Kondo S, Endo K, Tsuji A, Murono S & Yoshizaki T
(2012) Histopathology
Lymphangiogenesis in regional lymph nodes predicts nodal recurrence in pathological N0 squamous cell carcinoma of the tongue Aims: Cancer cells induce de‐novo lymphatic vessel growth within draining lymph nodes before they metastasize. The aim of this study was to retrospectively evaluate lymph node lymphangiogenesis before the establishment of nodal recurrence in squamous cell carcinoma (SCC) of the tongue. Methods and results: Surgical specimens from 28 patients with pT2–T3N0M0 SCC of the tongue after local excision with supraomohyoid neck dissection were studied by immunohistochemistry. Intranodal lymphatic endothelium was highlighted by podoplanin staining to evaluate lymphatic vessel counts (LVCs). Primary tumour sections were examined for the expression of lymphangiogenic factors: vascular endothelial growth factor (VEGF)‐C and VEGF‐D. LVCs in regional lymph nodes were significantly increased in the cases with nodal recurrence (P = 0.0013). Simultaneous increases in VEGF‐C and VEGF‐D expression were significantly associated with both an increase in LVC in regional lymph nodes (P = 0.0001) and a decrease in the rate of survival without nodal recurrence (P = 0.016). Conclusions: Knowing the status of lymphangiogenesis in the regional pN0 lymph nodes in tongue cancer would help in predicting which patients will develop nodal recurrence. The use of a therapeutic approach which blocks lymphangiogenic factors, such as VEGF‐C and VEGF‐D, may be beneficial in suppressing the lymphatic spread of tongue cancer with intense intranodal lymphangiogenesis.     

carbamoyl‐phosphate synthetase 2, aspartate transcarbamylase,and dihydroorotase (cad) regulates Notch signaling and vascular development in zebrafish

Background : The interplay between Notch and Vegf signaling regulates angiogenesis in the embryo. Notch signaling limits the responsiveness of endothelial cells to Vegf to control sprouting. Despite the importance of this regulatory relationship, much remains to be understood about extrinsic factors that modulate the pathway. Results : During a forward genetic screen for novel regulators of lymphangiogenesis, we isolated a mutant with reduced lymphatic vessel development. This mutant also exhibited hyperbranching arteries, reminiscent of Notch pathway mutants. Positional cloning identified a missense mutation in the carbamoyl‐phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (cad) gene. Cad is essential for UDP biosynthesis, which is necessary for protein glycosylation and de novo biosynthesis of pyrimidine‐based nucleotides. Using a transgenic reporter of Notch activity, we demonstrate that Notch signaling is significantly reduced in cad^hu10125 mutants. In this context, genetic epistasis showed that increased endothelial cell responsiveness to Vegfc/Vegfr3 signaling drives excessive artery branching. Conclusions : These findings suggest important posttranslational modifications requiring Cad as an unappreciated mechanism that regulates Notch/Vegf signaling during angiogenesis. Developmental Dynamics 244:1–9, 2015. © 2014 Wiley Periodicals, Inc.     

Coordinated lymphangiogenesis is critical in lymph node development and maturation

Background: Lymph node (LN) formation requires multiple but coordinated signaling from intrinsic and extrinsic cellular components during embryogenesis. However, the contribution and role of lymphatic vessels (LVs) in LN formation and maturation are poorly defined. Here, using lymphatic‐specific reporters, Prox1‐GFP mice and Vegfc^+/LacZ mice, we analyzed migration, assembly, and ingrowth of lymphatic endothelial cells (LECs) in LNs during pre‐ and postnatal development. Results: Prox1⁺ LECs form string‐like connections rather than lymph sac–like structures until E14.5, but the LEC coverage around LN anlagen completes before birth. Compared to wild‐type littermates, Vegfc^+/LacZ mice had markedly smaller LNs in neonates and adults, presumably due to the decrease in LTi cell clusters and migrating Prox1⁺ LECs during embryogenesis. In addition, Vegfc‐haploinsufficiency or inhibition of VEGFR3 signaling led to an impairment of LN LV ingrowth, resulting in a significant decrease in LN volume. These data indicate that VEGF‐C/VEGFR3 signaling plays a substantial role in normal LN formation through proper migration and organization of LECs. Conclusions: Taken together, our results provide compelling evidence that the contribution of LVs through VEGF‐C/VEGFR3 signaling is critical in LN development and maturation. Developmental Dynamics 245:1189–1197, 2016. © 2016 Wiley Periodicals, Inc.     

Mechanisms of lymphatic metastasis in human colorectal adenocarcinoma

The invasion of lymphatic vessels by colorectal cancer (CRC) and its subsequent spread to draining lymph nodes is a key determinant of prognosis in this common and frequently fatal malignancy. Although tumoural lymphangiogenesis is assumed to contribute to this process, review of the current literature fails to support any notion of a simple correlation between lymphatic vessel density and CRC metastasis. Furthermore, attempts to correlate the expression of various lymphangiogenic growth factors, most notably VEGF‐C and VEGF‐D, with the lymphatic metastasis of CRC have provided contradictory results. Recent evidence from animal and human models of tumour metastasis suggests that complex functional and biochemical interactions between the microvasculature of tumours and other cell types within the tumour microenvironment may play a pivotal role in the behaviour of commonly metastasizing tumours. Indeed, previous insights into tumoural blood vessels have provided candidate markers of tumoural angiogenesis that are currently the subject of intense investigation as future therapeutic targets. In this review article we survey the current evidence relating lymphangiogenesis and lymphangiogenic growth factor production to metastasis by CRC, and attempt to provide some insight into the apparent discrepancies within the literature. In particular, we also discuss some new and provocative insights into the properties of tumoural lymphatics suggesting that they have specific expression profiles distinct from those of normal lymphatic vessels and that appear to promote metastasis. These findings raise the exciting prospect of future biomarkers of lymphatic metastasis and identify potential targets for new generation anti‐tumour therapies. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.