Lymphatic microvessel density and vascular endothelial growth factor-C and -D as prognostic factors in breast cancer: a systematic review and meta-analysis of the literature

Hormone Receptor-Dependent Correlations Between Angiopoietins and VEGF-C in Primary Breast Cancer: Insights Into Lymphangiogenic Biomarkers

BACKGROUND

Biomarkers of angiogenesis and lymphangiogenesis have been explored in cancer prognostic models; however, their potential role in assessing local tumor invasiveness remains poorly understood.

AIMS

This study aimed to evaluate the correlations of angiogenic biomarkers, specifically the angiopoietin (ANG)-Tie system and vascular endothelial growth factor-C (VEGF-C), with lymphangiogenesis and the related histopathological characteristics in Iranian women with breast cancer.

METHODS AND RESULTS

In this consecutive case series (n = 149) from the Breast Cancer Risk and Lifestyle (BCRL) study, plasma levels of pro-angiogenic factors, including VEGF-C, ANGs, and Tie-2, were assessed using ELISA. Clinicopathological data were collected, excluding stage IV cases to focus on patients with localized disease. Axillary lymph node metastasis (ANLM), and vascular invasion (VI) were common in the study population, occurring in 61.5% and 77.6% of cases, respectively (p < 0.01). Estrogen receptor-positive (ER+) tumors were observed in 89.1% of ANLM+ participants, while human epidermal growth factor receptor-2-positive (HER-2+) tumors were identified in 22.8% of patients with ALNM. Plasma levels of ANG-1 (r = 0.19) and VEGF-C (r = 0.29) were positively correlated with the ALNM ratio (p < 0.05). Multivariate analysis in patients with grade II tumors revealed significant inverse correlations between VEGF-C and angiogenic biomarkers, including ANG-2 (β = -0.25), the ANG-2/Tie-2 ratio (β = -0.28), and the (ANG-1 + ANG-2)/Tie-2 ratio (β = -0.29) (p < 0.05). Receiver operating characteristic (ROC) curve analysis indicated that ANG-2 could effectively assess ALNM status, with an optimal cutoff of 3.39 pg/mL, identifying ALNM in 66.0% of patients with low VEGF-C levels (95% CI: 0.54-0.78), increasing to 68.0% when combined with ANG-1 as the ANGs/Tie-2 ratio (95% CI: 0.56-0.80). In ER+ tumors, high plasma ANG-2 levels were observed (p < 0.05). Significantly higher levels of the (ANG-1 + ANG-2)/VEGF-C ratio were noted in patients with VI+ (p < 0.05). Findings descriptively highlighted ER+ status as a common characteristic in VI+ and ALNM+ tumors. In HER-2+ patients, both ANG-1 and the (ANG-1 + ANG-2)/Tie-2 ratio showed inverse correlations with VEGF-C, while in ER- breast cancer patients, ANG-2 was inversely correlated with VEGF-C.

CONCLUSION

These findings provide new insights into the inverse correlation between plasma levels of ANGs and VEGF-C, particularly in cases with positive ALNM, underscoring the role of hormone receptor-dependent characteristics. The integration of the triple angiogenic biomarkers ANG-2/Tie-2/VEGF-C within the tumor microenvironment, combined with the regulatory influence of hormonal receptors, merits further investigation as a potential biomarker panel for identifying lymphatic anomalies and VI positivity in breast cancer patients.

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.

Decorin suppresses tumor lymphangiogenesis: A mechanism to curtail cancer progression

The complex interplay between malignant cells and the cellular and molecular components of the tumor stroma is a key aspect of cancer growth and development. These tumor-host interactions are often affected by soluble bioactive molecules such as proteoglycans. Decorin, an archetypical small leucine-rich proteoglycan primarily expressed by stromal cells, affects cancer growth in its soluble form by interacting with several receptor tyrosine kinases (RTK). Overall, decorin leads to a context-dependent and protracted cessation of oncogenic RTK activity by attenuating their ability to drive a prosurvival program and to sustain a proangiogenic network. Through an unbiased transcriptomic analysis using deep RNAseq, we identified that decorin down-regulated a cluster of tumor-associated genes involved in lymphatic vessel (LV) development when systemically delivered to mice harboring breast carcinoma allografts. We found that Lyve1 and Podoplanin, two established markers of LVs, were markedly suppressed at both the mRNA and protein levels, and this suppression correlated with a significant reduction in tumor LVs. We further identified that soluble decorin, but not its homologous proteoglycan biglycan, inhibited LV sprouting in an ex vivo 3D model of lymphangiogenesis. Mechanistically, we found that decorin interacted with vascular endothelial growth factor receptor 3 (VEGFR3), the main lymphatic RTK, and its activity was required for the decorin-mediated block of lymphangiogenesis. Finally, we identified that Lyve1 was in part degraded via decorin-evoked autophagy in a nutrient- and energy-independent manner. These findings implicate decorin as a biological factor with antilymphangiogenic activity and provide a potential therapeutic agent for curtailing breast cancer growth and metastasis.

Vascular endothelial growth factor (VEGF) -A, -C and VE-cadherin as potential biomarkers in early breast cancer patients

BACKGROUND

Vascular endothelial growth factor (VEGF) -A and -C act as multifunctional molecules and growth factors, while VE-cadherin (cadherin 5, CDH5) is the endothelial junction protein.

AIM

To assess the relationship between intratumoral VEGF -A, -C and CDH5 levels and clinical outcome, in primary, early-stage, breast cancer patients.

PATIENTS AND METHODS

The study included 69 node-negative (N0) breast cancer patients, all of whom had not received any prior hormonal or chemotherapeutic systemic therapy that would affect the course of disease. The median follow-up period was 144 months. Intratumoral mRNA levels of VEGF -A, -C and CDH5 were determined by RT-qPCR. Prognostic performance was evaluated by Cox proportional hazards regression, Kaplan-Meier analysis, as well as by the multivariable approach based on the least absolute shrinkage and selection operator (LASSO) logit regression. Classification of patients into the low and high subgroups was performed using the outcome-oriented cut-off point categorization approach.

RESULTS

Of the measured mRNAs, only CDH5 mRNA (t = -2.17; p = 0.04) and VEGF-C mRNA (t = -2.41; p = 0.03) showed significant differences between values in patient subgroups with distant metastasis and those without recurrences, respectively. These t-test results were in agreement with the Cox regression by which CDH5 mRNA reached the most pronounced hazard ratio (HR=2.07; p = 0.05), followed by VEGF-C mRNA (HR=1.59; p = 0.005). HR values above 1.0 indicate that high levels of either CDH5 or VEGF-C mRNAs associated with a higher risk of poor clinical outcome. Distant recurrence incidence was 26% for the CDH5high and 3% for the CDH5low subgroup (Kaplan-Meier analysis). Distant recurrence incidence was 23% for the VEGF-Chigh and 0% for VEGF-Clow subgroup. The independent prognostic value of VEGF-C mRNA was confirmed by LASSO regression.

CONCLUSION

Intratumoral VEGF-A levels did not associate with disease outcome in primary, early-stage, breast cancer patients, whilst raised levels of either CDH5 or VEGF-C prognosticated a high risk of distant metastasis.

Decorin suppresses tumor lymphangiogenesis: A mechanism to curtail cancer progression

The complex interplay between malignant cells and the cellular and molecular components of the tumor stroma is a key aspect of cancer growth and development. These tumor-host interactions are often affected by soluble bioactive molecules such as proteoglycans. Decorin, an archetypical small leucine-rich proteoglycan primarily expressed by stromal cells, affects cancer growth in its soluble form by interacting with several receptor tyrosine kinases (RTK). Overall, decorin leads to a context-dependent and protracted cessation of oncogenic RTK activity by attenuating their ability to drive a pro-survival program and to sustain a pro-angiogenic network. Through an unbiased transcriptomic analysis using deep RNAseq, we discovered that decorin downregulated a cluster of tumor-associated genes involved in lymphatic vessel development when systemically delivered to mice harboring breast carcinoma allografts. We found that Lyve1 and Podoplanin, two established markers of lymphatic vessels, were markedly suppressed at both the mRNA and protein levels and this suppression correlated with a significant reduction in tumor lymphatic vessels. We further discovered that soluble decorin, but not its homologous proteoglycan biglycan, inhibited lymphatic vessel sprouting in an ex vivo 3D model of lymphangiogenesis. Mechanistically, we found that decorin interacted with VEGFR3, the main lymphatic RTK, and its activity was required for the decorin-mediated block of lymphangiogenesis. Finally, we discovered that Lyve1 was in part degraded via decorin-evoked autophagy in a nutrient- and energy-independent manner. These findings implicate decorin as a new biological factor with anti-lymphangiogenic activity and provide a potential therapeutic agent for curtailing breast cancer growth and metastasis.

High VEGFR3 Expression Reduces Doxorubicin Efficacy in Triple-Negative Breast Cancer

Due to the lack of specific targets, cytotoxic chemotherapy still represents the common standard treatment for triple-negative breast patients. Despite the harmful effect of chemotherapy on tumor cells, there is evidence that treatment could modulate the tumor microenvironment in a way favoring the propagation of the tumor. In addition, the lymphangiogenesis process and its factors could be involved in this counter-therapeutic event. In our study, we have evaluated the expression of the main lymphangiogenic receptor VEGFR3 in two triple-negative breast cancer in vitro models, resistant or not to doxorubicin treatment. The expression of the receptor, at mRNA and protein levels, was higher in doxorubicin-resistant cells than in parental cells. In addition, we confirmed the upregulation of VEGFR3 levels after a short treatment with doxorubicin. Furthermore, VEGFR3 silencing reduced cell proliferation and migration capacities in both cell lines. Interestingly, high VEGFR3 expression was significantly positively correlated with worse survival in patients treated with chemotherapy. Furthermore, we have found that patients with high expression of VEGFR3 present shorter relapse-free survival than patients with low levels of the receptor. In conclusion, elevated VEGFR3 levels correlate with poor survival in patients and with reduced doxorubicin treatment efficacy in vitro. Our results suggest that the levels of this receptor could be a potential marker of meager doxorubicin response. Consequently, our results suggest that the combination of chemotherapy and VEGFR3 blockage could be a potentially useful therapeutic strategy for the treatment of triple-negative breast cancer.

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.

Platinum Chemotherapy Induces Lymphangiogenesis in Cancerous and Healthy Tissues That Can be Prevented With Adjuvant Anti-VEGFR3 Therapy

Chemotherapy has been used to inhibit cancer growth for decades, but emerging evidence shows it can affect the tumor stroma, unintentionally promoting cancer malignancy. After treatment of primary tumors, remaining drugs drain via lymphatics. Though all drugs interact with the lymphatics, we know little of their impact on them. Here, we show a previously unknown effect of platinums, a widely used class of chemotherapeutics, to directly induce systemic lymphangiogenesis and activation. These changes are dose-dependent, long-lasting, and occur in healthy and cancerous tissue in multiple mouse models of breast cancer. We found similar effects in human ovarian and breast cancer patients whose treatment regimens included platinums. Carboplatin treatment of healthy mice prior to mammary tumor inoculation increased cancer metastasis as compared to no pre-treatment. These platinum-induced phenomena could be blocked by VEGFR3 inhibition. These findings have implications for cancer patients receiving platinums and may support the inclusion of anti-VEGFR3 therapy into treatment regimens or differential design of treatment regimens to alter these potential effects.

Opposing Roles of Vascular Endothelial Growth Factor C in Metastatic Dissemination and Resistance to Radio/Chemotherapy: Discussion of Mechanisms and Therapeutic Strategies

Many cancers can be cured by combining surgery with healthy margins, radiation therapy and chemotherapies. However, when the pathology becomes metastatic, cancers can be incurable. The best situation involves "chronicization" of the pathology even for several years. However, most of the time, patients die within a few months. To disseminate throughout the body, cancer cells must enter the vascular network and seed in another organ. However, during the initiation of cancer processes, the tumor is avascular. Later, the production of angiogenic factors causes tumor neovascularization and subsequent growth and spread, and the presence of blood and/or lymphatic vessels is associated with high grade tumors. Moreover, during tumor development, cancer cells enter lymphatic vessels and disseminate via the lymphatic network. Hence, blood and lymphatic vessels are considered as main routes of metastatic dissemination and cancer aggressiveness. Therefore, anti-angiogenic drugs entered in the therapeutic arsenal from 2004. Despite undeniable effects however, they are far from curative and only prolong survival by a few months.Recently, the concepts of angio/lymphangiogenesis were revisited by analyzing the role of blood and lymphatic vessels at the initiation steps of tumor development. During this period, cancer cells enter lymphatic vessels and activate immune cells within lymph nodes to initiate an antitumor immune response. Moreover, the presence of blood vessels at the proximity of the initial nodule allows immune cells to reach the tumor and eliminate cancer cells. Therefore, blood and lymphatic networks have a beneficial role during a defined time window. Considering only their detrimental effects is a concern. Hence, administration of anti-angio/lymphangiogenic therapies should be revisited to avoid the destruction of networks involved in antitumor immune response. This review mainly focuses on one of the main drivers of lymphangiogenesis, the VEGFC and its beneficial and pejorative roles according to the grade of aggressive tumors.

Early Imaging and Molecular Changes with Neoadjuvant Bevacizumab in Stage II/III Breast Cancer

This prospective, phase II study evaluated novel biomarkers as predictors of response to bevacizumab in patients with breast cancer (BC), using serial imaging methods and gene expression analysis. Patients with primary stage II/III BC received bevacizumab 15 mg/kg (cycle 1; C1), then four cycles of neoadjuvant docetaxel doxorubicin, and bevacizumab every 3 weeks (C2-C5). Tumour proliferation and hypoxic status were evaluated using 18F-fluoro-3'-deoxy-3'-L-fluorothymidine (FLT)- and 18F-fluoromisonidazole (FMISO)-positron emission tomography (PET) at baseline, and during C1 and C5. Pre- and post-bevacizumab vascular changes were evaluated using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Molecular biomarkers were assessed using microarray analysis. A total of 70 patients were assessed for treatment efficacy. Significant decreases from baseline in tumour proliferation (FLT-PET), vascularity, and perfusion (DCE-MRI) were observed during C1 (p ≤ 0.001), independent of tumour subtype. Bevacizumab treatment did not affect hypoxic tumour status (FMISO-PET). Significant changes in the expression of 28 genes were observed after C1. Changes in vascular endothelial growth factor receptor (VEGFR)-2p levels were observed in 65 patients, with a > 20% decrease in VEGFR-2p observed in 13/65. Serial imaging techniques and molecular gene profiling identified several potentially predictive biomarkers that may predict response to neoadjuvant bevacizumab therapy in BC patients.

Docetaxel facilitates lymphatic-tumor crosstalk to promote lymphangiogenesis and cancer progression

Background

Infiltration into lymphatic vessels is a critical step in breast cancer metastasis. Lymphatics undergo changes that facilitate metastasis as a result of activation of the cells lining lymphatic vessels, lymphatic endothelial cells (LECs). Inhibition of activation by targeting VEGFR3 can reduce invasion toward lymphatics. To best benefit patients, this approach should be coupled with standard of care that slows tumor growth, such as chemotherapy. Little is known about how chemotherapies, like docetaxel, may influence lymphatics and conversely, how lymphatics can alter responses to therapy.

Methods

A novel 3D in vitro co-culture model of the human breast tumor microenvironment was employed to examine the contribution of LECs to tumor invasion and viability with docetaxel and anti-VEGFR3, using three cell lines, MDA-MB-231, HCC38, and HCC1806. In vivo, the 4T1 mouse model of breast carcinoma was used to examine the efficacy of combinatorial therapy with docetaxel and anti-VEGFR3 on lymph node metastasis and tumor growth. Lymphangiogenesis in these mice was analyzed by immunohistochemistry and flow cytometry. Luminex analysis was used to measure expression of lymphangiogenic cytokines.

Results

In vitro, tumor cell invasion significantly increased with docetaxel when LECs were present; this effect was attenuated by inhibition of VEGFR3. LECs reduced docetaxel-induced cell death independent of VEGFR3. In vivo, docetaxel significantly increased breast cancer metastasis to the lymph node. Docetaxel and anti-VEGFR3 combination therapy reduced lymph node and lung metastasis in 4T1 and synergized to reduce tumor growth. Docetaxel induced VEGFR3-dependent vessel enlargement, lymphangiogenesis, and expansion of the LEC population in the peritumoral microenvironment, but not tumor-free stroma. Docetaxel caused an upregulation in pro-lymphangiogenic factors including VEGFC and TNF-α in the tumor microenvironment in vivo.

Conclusions

Here we present a counter-therapeutic effect of docetaxel chemotherapy that triggers cancer cells to elicit lymphangiogenesis. In turn, lymphatics reduce cancer response to docetaxel by altering the cytokine milieu in breast cancer. These changes lead to an increase in tumor cell invasion and survival under docetaxel treatment, ultimately reducing docetaxel efficacy. These docetaxel-induced effects can be mitigated by anti-VEGFR3 therapy, resulting in a synergism between these treatments that reduces tumor growth and metastasis.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4619-8) contains supplementary material, which is available to authorized users.

Loss of PTEN expression in breast cancer: association with clinicopathological characteristics and prognosis

Various studies have evaluated the significance of PTEN (phosphatase and tensin homolog deleted from chromosome 10) expression in breast cancer, but their results remain controversial. We conducted a meta-analysis to evaluate the associations of PTEN expression with clinicopathological characteristics and prognosis in breast cancer. PubMed, Embase, Web of Science, and China National Knowledge Infrastructure were searched to identify relevant publications. The associations between PTEN expression and clinicopathological parameters, disease-free survival (DFS), and overall survival (OS) were then assessed via meta-analyses of odds ratio (ORs) and hazard ratio (HRs) with 95% confidence intervals (CIs). Based on 27 studies involving 10,231 patients, the pooled results revealed that PTEN loss was significantly more common in breast cancer than in normal tissues (OR = 12.15, 95% CI = 6.48–22.79, P < 0.00001) and that PTEN loss had clear associations with larger tumor size (> 2 cm, OR = 0.62, 95% CI = 0.48–0.82, P= 0.0006), lymph node metastasis(OR = 0.61, 95% CI = 0.45–0.82, P = 0.0001), later TNM stage(stage III–IV, OR = 0.55, 95% CI = 0.35–0.86, P= 0.009), poor differentiation(OR = 0.37, 95% CI = 0.24–0.59, P < 0.0001), and the highly aggressive triple-negative phenotype (OR = 1.62, 95% CI = 1.23–2.12, P = 0.0005). Moreover, patients with PTEN loss exhibited significantly worse DFS and OS(HR = 1.63, 95% CI = 1.04–2.22, P < 0.00001; HR = 1.41, 95% CI = 1.08–1.73, P < 0.0001; respectively). In conclusion, PTEN loss might predict more aggressive behavior and worse outcomes in patients with breast cancer.

A meta-analysis of the lymphatic microvessel density and survival in gastric cancer with 1809 cases

Lymph node metastasis commonly occurs in gastric cancer. Previous studies have demonstrated that the overexpression of lymphatic microvessel density (LVD) is correlated with various malignancies. To evaluate the potential role of LVD in various malignancies, we conducted a systematic review and meta-analysis to thoroughly investigate the association of LVD expression with tumor progression and survival in gastric cancer. We performed a comprehensive search of common databases and selected studies demonstrating the relationship between LVD expression and gastric cancer prognosis. Hazard ratios (HR) were used to determine the value of LVD for predicting gastric cancer metastasis and prognosis. The data were extracted from the included studies and pooled with the appropriate effects model using STATA 12.0. The results showed that high LVD expression obviously impacted the prognosis of gastric cancer, based on an overall survival (OS) HR of 2.58 (95% CI: 1.91-3.48, P < 0.001) and a disease-free survival (DFS) HR of 2.51 (95% CI: 1.35-4.68, P = 0.004) in the univariate analysis. In addition, the results of the multivariate analysis indicated a remarkable relationship between high LVD expression and gastric neoplasm prognosis. The pooled OS HR was 4.12 (95% CI: 3.45-4.91, P < 0.001). The current meta-analysis shows that high LVD is closely related to tumor metastasis and poor prognosis in gastric malignancy. LVD could be a key factor in tumor lymphatic metastasis. Moreover, LVD is likely a potential index and an effective biomarker for the prediction of patient prognosis.

High Expression of Retinoblastoma-Binding Protein 2 (RBP2) in Patients with Hepatocellular Carcinoma and Its Prognostic Significance

Background

Recently, some studies have found that retinoblastoma-binding protein 2 (RBP2) is involved in the development and progression of many kinds of malignant tumors. This study aimed to explore the expression level of RBP2 in hepatocellular carcinoma (HCC) and its prognostic significance.

Material/Methods

Immunohistochemical analysis was used to evaluate the RBP2 expression level in 130 HCC patients and adjacent normal tissues. Tumor angiogenesis was marked by CD31 and vascular endothelial growth factor (VEGF) staining. Kaplan-Meier and Cox regression analyses were performed to examine the relationship between RBP2 expression and prognosis of HCC patients.

Results

RBP2 expression was significantly higher in HCC tissues (positive expression rate: 72.3%, 94/130). Increased RBP2 expression was dramatically associated with AFP level (P=0.016), degree of differentiation (P=0.000), and TNM stage (P=0.035). Moreover, tumors with RBP2-positive expression showed significantly higher intratumoral MVD than those with RBP2-negative expression (P=0.000). Kaplan-Meier analysis revealed RBP2-positive expression was related to decreased disease-free survival (DFS) (P=0.000) and overall survival (OS) (P=0.000). Furthermore, RBP2 was an independent poor prognostic factor of DFS and OS (P=0.029 and 0.010, respectively) as demonstrated by multivariate analysis.

Conclusions

Increased RBP2 expression, as an independent poor prognostic factor for DFS and OS of HCC patients, is closely related to tumor angiogenesis. RBP2 is expected to become a new potential therapeutic target for HCC.

New Mechanisms of Tumor-Associated Macrophages on Promoting Tumor Progression: Recent Research Advances and Potential Targets for Tumor Immunotherapy

The majority of basic and clinical studies have shown a protumor function of tumor-associated macrophages (TAMs), which represent a large proportion of matrix cells. TAMs promote tumorigenesis, and their number is related to the malignancy degree and poor prognosis of many kinds of tumors. Macrophage plasticity makes it possible to change the tumor microenvironment and remodel antitumor immunity during cancer immunotherapy. Increasing numbers of studies have revealed the effects of TAMs on the tumor microenvironment, for example, via promotion of tumor growth and tumorigenesis and through an increase in the number of cancer stem cells or via facilitation of angiogenesis, lymphangiogenesis, and metastasis. Investigators also proposed tumor-immunological treatments targeting TAMs by inhibiting TAM recruitment and differentiation, by regulating TAM polarization, and by blocking factors and pathways associated with the protumor function of TAMs. This comprehensive review presents recent research on TAMs in relation to prediction of poor outcomes, remodeling of the tumor immune microenvironment, and immunological targeted therapies.

Prognostic Significance of High VEGF-C Expression for Patients with Breast Cancer: An Update Meta Analysis

BACKGROUND

The prognostic significance of vascular endothelial growth factor C (VEGF-C) expression in breast cancer (BC) patients remains controversial. Therefore, this meta-analysis was performed to determine the prognostic significance of VEGF-C expression in BC patients.

MATERIALS AND METHODS

Several electronic databases were searched from January 1991 to August 2016. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate the prognostic significance of VEGF-C expression for disease free survival (DFS) and overall survival (OS).

RESULTS

The present meta analysis totally included 21 eligible studies and 2828 patients with BC. The combined HRs were 1.87(95% CI 1.25-2.79, P = 0.001) for DFS and 1.96(95% CI 1.15-3.31, P = 0.001) for OS. The pooled HRs of non-Asian subgroup were 2.04(95%CI 1.36-3.05, P = 0.001) for DFS and 2.61(95%CI 1.51-4.52, P = 0.001) for OS, which were significantly higher than that of Asian subgroup. The funnel plot for publication bias was symmetrical. The further Egger's test and Begg's test did not detect significant publication bias (all P>0.05).

CONCLUSIONS

The present meta analysis strongly supported the prognostic role of VEGF-C expression for DFS and OS in BC patients, especially for patients in non-Asian countries. Furthermore, stratification by VEGF-C expression may help to optimize the treatments and the integrated managements for BC patients.

Multivariate analysis of metastasis‑related risk factors for patients with gastroenteropancreatic neuroendocrine tumors based on clinicopathological and endoscopic features

Gastroenteropancreatic neuroendocrine tumors (GEP‑NETs) are relatively uncommon. Unfortunately, epidemiological studies on the incidence of GEP‑NETs worldwide have reported a marked increase in the detection of these tumors. Although they often exhibit relatively indolent clinical courses, GEP‑NETs have the potential for lethal progression, especially in patients who present with advanced disease. Early detection and surgical removal is currently the only reliable curative treatment for GEP‑NET patients. The objective of this study was to analyze the clinicopathological characteristics of GEP‑NETs and explore the metastasis‑related risk factors of patients with GEP‑NETs. One hundred and forty‑six patients diagnosed pathologically with GEP‑NETs from January 2001 to January 2015 at the Second Xiangya Hospital of Central South University were retrospectively evaluated. We retrieved and analyzed information concerning clinical characteristics and metastasis‑related risk factors, and used Chi‑square test and logistic regression analysis to analyze the clinicopathological characteristics of GEP‑NETs and explore the association between tumor metastasis and possible related risk factors. The results revealed that the most common clinical manifestations were abdominal pain (n=88), alteration in the character of stool (n=58) and melaena (n=33). Rectum (91/146, 62.3%) and stomach (19/146, 13.0%) were the main sites of metastasis. Both Chi‑square test and logistic regression analysis showed that tumor size (P<0.05), tumor type (P=0.008) and peritumoral lymphatic vessel density (LVD) (P=0.004) were significantly correlated with tumor metastasis. Neither Chi‑square test nor logistic regression analysis indicated that gender (P>0.05), age (P>0.05), tumor location (P>0.05), tumor number (P>0.05), chromaffin granule protein A [chromogranin A (CgA), P>0.05], synaptophysin (Syn, P>0.05) or intratumoral LVD (P>0.05) had a significant correlation with tumor metastasis. Chi‑square test revealed that tumor grade was significantly correlated with tumor metastasis. In conclusion, GEP‑NETs may occur in multiple sites of the digestive system and lack specific clinical manifestations. Tumor size, tumor type, peritumoral LVD, total LVD and tumor grade are metastasis‑related risk factors for GEP‑NET patients.

The role of lymphangiogenesis and angiogenesis in tumor metastasis

BACKGROUND

Metastasis is the main cause of mortality in cancer patients. Two major routes of cancer cell spread are currently being recognized: dissemination via blood vessels (hematogenous spread) and dissemination via the lymphatic system (lymphogenous spread). Here, our current knowledge on the role of both blood and lymphatic vessels in cancer cell metastasis is summarized. In addition, I will discuss why cancer cells select one or both of the two routes to disseminate and I will provide a short description of the passive and active models of intravasation. Finally, lymphatic vessel density (LVD), blood vessel density (BVD), interstitial fluid pressure (IFP) and tumor hypoxia, as well as regional lymph node metastasis and the recently discovered primo vascular system (PVS) will be highlighted as important factors influencing tumor cell motility and spread and, ultimately, clinical outcome.

CONCLUSIONS

Lymphangiogenesis and angiogenesis are important phenomena involved in the spread of cancer cells and they are associated with a poor prognosis. It is anticipated that new discoveries and advancing knowledge on these phenomena will allow an improvement in the treatment of cancer patients.

Sunitinib alone or in combination with chemotherapy for the treatment of advanced breast cancer: A systematic review and meta-analysis

INTRODUCTION

Sunitinib is an orally delivered tyrosine kinase inhibitor that exhibits antiangiogenic effects. FDA has approved sunitinib for the treatment of metastatic renal cell carcinoma. However, its efficacy for the treatment of advanced breast cancer (ABC) remains controversial. Therefore, we performed this systematic review and meta-analysis to synthesize evidence from published randomized controlled trials (RCTs) about the efficacy of sunitinib alone and in combination with chemotherapy for the treatment of ABC.

METHODS

We followed PRISMA statement guidelines during the preparation of this systematic review and meta-analysis. A computer literature search of PubMed, SCOPUS, web of knowledge, and Cochrane Central Register of Controlled Trials (CENTRAL) has been conducted using relevant keywords. Studies were screened for eligibility and data were extracted to an online data extraction form. Progression free survival (PFS) and overall survival (OS) were pooled as Hazard ratio (HR) in a meta-analysis model using generic inverse variance method. Objective response rate (ORR) and complications were pooled as relative risk (RR) in a random effect model meta-analysis using Mantel-Haenzel method.

RESULTS

Six RCTs, with a total sample size of 2273 patients, met our eligibility criteria and were included in this meta-analysis. Sunitinib monotherapy was not superior to chemotherapy in terms of PFS (HR = 1.00, 95% CI [0.86 to 1.16], P = 0.99), OS (HR = 1.07; 95% CI [0.87 to 1.32], P = 0.5), or ORR (RR = 0.70, 95% CI [0.74 to 1.03], P = 0.07). Sunitinib in combination with chemotherapy did not show superiority to chemotherapy in terms of PFS (HR = 0.99, 95% CI [0.86 to 1.14], P = 0.89) and OS (HR = 1.04, 95% CI [0.85 to 1.28], P = 0.69). However, the ORR favored sunitinib in combination with chemotherapy group (RR = 1.15, 95% CI [1.01 to 1.31]) with a statistically significant P value (P = 0.03).

CONCLUSIONS

Current evidence shows that sunitinib, either alone or in combination with chemotherapy, has no clinical benefit for patients with advanced breast cancer. However, previous studies did not considered patient stratification and outcome assessment based on molecular markers. In terms of safety, toxicity was common with sunitinib treatment.

Predictive role of the overexpression for CXCR4, C-Met, and VEGF-C among breast cancer patients: A meta-analysis

BACKGROUND

The overexpression of CXCR4, C-Met and VEGF-C present widely in breast tumors, they may be markers of resistance to treatment. However, the studies are still controversial. Thus, this meta-analysis aims to research the relationship between the overexpression of CXCR4, C-Met, VEGF-C and clinical prognosis among breast cancer patients.

METHODS

PubMed and EMBASE databases were searched for eligible literature. The outcomes of interest were progression-free survival (PFS), relapse-free survival (RFS) and overall survival (OS). All tests of statistical significance were two sided.

RESULTS

A total of 7830 patients from 28 eligible studies were assessed. The overexpression of the CXCR4 and C-Met both implied significantly worse PFS compared with normal expression [HR = 2.56, 95% CI = 1.34-4.91, P = 0.005; and HR = 1.63 95% CI = 1.20-2.22, P = 0.002]. Meanwhile, if patients had high expression of CXCR4, they would have worse OS [HR = 2.56 95% CI = 1.52-4.31, P = 0.000]. However, the overexpression of C-Met did not relate to OS for breast cancer patients [HR = 1.16, 95% CI = 0.69-1.95, P = 0.570]. Meanwhile, no statistically significant different was observed with respect to PFS and OS between VEGF-C overexpression and normal expression [HR = 0.99, 95% CI = 0.64-1.52, P = 0.968; and HR = 0.76, 95% CI = 0.43-1.33, P = 0.333].

CONCLUSIONS

Our meta-analysis showed that CXCR4 and C-Met were efficient prognostic factors for breast cancer. Nevertheless, highly expressing VEGF-C was not related to progression-free survival and overall survival. Due to the small samples and insufficient date, further studies should be conducted to clarify the association between the overexpression of CXCR4 or C-Met or VEGF-C and the prognosis about breast cancer patients.

VEGF-D-enhanced lymph node metastasis of ovarian cancer is reversed by vesicular stomatitis virus matrix protein

Lymphatic metastasis is a poor prognostic factor in ovarian cancer, which correlates to the majority of cancer deaths. Matrix protein (MP) of vesicular stomatitis virus (VSV) exhibits potent antitumor and antiangiogenic activities through inducing apoptosis and inhibiting angiogenesis. In this study, the antitumor and antimetastatic effects of MP were further investigated. Wild-type SKOV3 (WT-SK) cells were successfully transfected with empty vector pcDNA3.1 plasmid, or pcDNA3.1-VEGF-D recombinant plasmid to construct cell lines named EV-SK, and VEGFD-SK, respectively. Inhibition of VEGFD-SK cell migration and invasion was detected by Transwell and wound healing assay. Then, lymphogenous metastatic model of ovarian cancer was established by injecting VEGFD-SK cells subcutaneously into the left hindlimb claw pad of nude mice. The inducted apoptotic effect of MP on VEGFD-SK cells were assessed by flow analysis and Hoechst-33258 staining, respectively, in vitro. The in vivo antitumor and antiangiogenic activities of MP gene were evaluated with lymphogenous metastatic model of ovarian cancer. Tumor volume and lymphatic metastasis rates were measured. Lymphatic vessels were delineated using Evan's blue and LYVE-1 staining. Expression of VEGF-D and MMP-2 were evaluated by immunostaining. Apoptosis of tumor cells was analyzed by Hoechst-33258 staining. Mice bearing VEGFD-SK tumor cells displayed more rapid tumorigenesis, higher lymphogenous metastatic tendency and increased lymphatic vessel density compared with the mice bearing WT-SK or EV-SK cells. However, VEGF-D-enhanced metastasis was evidently reversed by MP. MP significantly reduced the invasion of VEGFD-SK cells, tumor volume, lymphatic metastasis rates and lymphatic vessel density compared with control groups (P<0.05), accompanied with down-expression of VEGF-D and MMP-2 and increased apoptosis. Our data indicate that MP has strong antitumor and antimetastatic abilities, and it may be a promising therapeutic strategy against the lymphatic metastasis of human ovarian cancer.

Assessing Tumor Angiogenesis in Histological Samples

Tumor neovascularization acquires their vessels through a number of processes including angiogenesis, vasculogenesis, vascular remodeling, intussusception, and possibly vascular mimicry in certain tumors. The end result of the tumor vasculature has been quantified by counting the number of immunohistochemically identified microvessels in areas of maximal vascularity, so-called hot spot. Other techniques have been developed such as Chalkley counting and the use of image analysis systems that are robust and reproducible as well as being more objective. Many of the molecular pathways that govern tumor neovascularization have been identified and many reagents are now available to study these tissue sections. These include angiogenic growth factors and their receptors and cell adhesion molecules, proteases, and markers of activated, proliferating, cytokine-stimulated, or angiogenic vessels, such as CD105. It is also possible to differentiate quiescent from active vessels. Other reagents that can identify proteins involved in microenvironmental influences such as hypoxia have also been generated. Although the histological assessment of tumor vascularity is used mostly in the research context, it may also have clinical applications if appropriate methodology and trained observers perform the studies.

A potential small-molecule synthetic antilymphangiogenic agent norcantharidin inhibits tumor growth and lymphangiogenesis of human colonic adenocarcinomas through blocking VEGF-A,-C,-D/VEGFR-2,-3 "multi-points priming" mechanisms in vitro and in vivo

Background

Tumor lymphangiogenesis plays an important role in promoting growth and metastasis of tumors, but no antilymphangiogenic agent is used clinically. Based on the effect of norcantharidin (NCTD) on lymphangiogenesis of human lymphatic endothelial cells (LECs), we firstly investigated the antilymphangiogenic activity of NCTD as a tumor lymphangiogenic inhibitor for human colonic adenocarcinomas (HCACs).

Methods

In vivo and in vitro experiments to determine the effects of NCTD on tumor growth and lymphangiogenesis of the in-situ colonic xenografts in nude mice, and lymphatic tube formation of the three-dimensional (3-D) of the co-culture system of HCAC HT-29 cells and LECs were done. Proliferation, apoptosis, migration, invasion, Ki-67, Bcl-2 and cell cycle of LECs and the co-culture system in vitro were respectively determined. Streparidin-peroxidase staining, SABC, western blotting and RT-PCR were respectively used to examine the expression of LYVE-1, D2-40, CK20 (including their LMVD), and VEGF-A, VEGF-C, VEGF-D, VEGFR-2 and VEGFR-3 in vitro and in vivo.

Results

NCTD inhibited tumor growth and lymphangiogenesis of the in-situ colonic xenografts in vivo, and these observations were confirmed by facts that lymphatic tube formation, proliferation, apoptosis, migration, invasion, S-phase cell cycle, and Ki-67 and Bcl-2 expression in vitro, and LYVE-1, D2-40, CK20 expression and their LMVD in vitro and in vivo were inhibited and affected. Furthermore, the expression of VEGF-A, VEGF-C, VEGF-D, VEGFR-2 and VEGFR-3 at protein/mRNA levels in the process of lymphatic tube formation in vitro and tumor lymphangiogenesis in vivo was downregulated; NCTD in combination with mF4-31C1 or Sorafenib enhanced these effects.

Conclusions

NCTD inhibits tumor growth and lymphangiogenesis of HCACs through “multi-points priming” mechanisms i.e. affecting related malignant phenotypes, inhibiting Ki-67 and Bcl-2 expression, inducing S-phase cell cycle arrest, and directly or indirectly downregulating VEGF-A,-C,-D/VEGFR-2,-3 signaling pathways. The present finding strongly suggests that NCTD could serve as a potential antilymphangiogenic agent for tumor lymphangiogenesis and is of importance to explore NCTD is used for antitumor metastatic comprehensive therapy for HCACs.

The importance of the tumor microenvironment in the therapeutic management of cancer

Tumor prognosis is generally defined by various tumor parameters. However, it is well known that paracrine, endocrine and cell-cell interactions between the tumor and its microenvironment contribute to its growth. The tumor microenvironment (TME) can also influence disease prognosis and is likely to be considered as an important prognostic factor. In addition, conventional therapies can influence the microenvironment and antitumor immunity. Similarly, the TME will influence the effectiveness of therapy. The purpose of this review is to demonstrate how TME is important in therapeutic management. Key interactions between TME and different cancer therapies as well as their current clinical consequences have been described. More research is needed to establish the important network between tumor cells and their environment to highlight their relationships with conventional therapies and develop global therapeutic strategies.

Full-Length Semaphorin-3C Is an Inhibitor of Tumor Lymphangiogenesis and Metastasis

Semaphorins play important regulatory roles in diverse processes such as axon guidance, angiogenesis, and immune responses. We find that semaphorin-3C (sema3C) induces the collapse of the cytoskeleton of lymphatic endothelial cells (LEC) in a neuropilin-2-, plexin-D1-, and plexin-A1-dependent manner, while most other semaphorins, including antiangiogenic semaphorins such as sema3A do not. Sema3C is cleaved, like other class-3 semaphorins, by furin-like pro-protein convertases (FPPC). Cleaved sema3C (p65-Sema3C) was unable to induce the collapse of the cytoskeleton of LEC. FPPC are strongly upregulated in tumor cells. In order to examine the effects of full-length sema3C on tumor progression, we therefore generated an active point mutated furin cleavage-resistant sema3C (FR-sema3C). FR-sema3C inhibited potently proliferation of LEC and to a lesser extent proliferation of human umbilical vein-derived endothelial cells. FR-sema3C also inhibited VEGF-C-induced phosphorylation of VEGFR-3, ERK1/2, and AKT. Expression of recombinant FR-sema3C in metastatic, triple-negative LM2-4 breast cancer cells did not affect their migration or proliferation in vitro. However, tumors derived from FR-sema3C-expressing LM2-4 cells implanted in mammary fat pads developed at a slower rate, contained a lower concentration of blood vessels and lymph vessels, and metastasized much less effectively to lymph nodes. Interestingly, p65-Sema3C, but not FR-sema3C, rendered A549 lung cancer cells resistant to serum deprivation, suggesting that previously reported protumorigenic activities of sema3C may be due to p65-Sema3C produced by tumor cells. Our observations suggest that FR-sema3C may be further developed into a novel antitumorigenic drug.

Blood microvessel density, lymphatic microvessel density and lymphatic invasion in predicting melanoma metastases: systematic review and meta-analysis

In malignant melanoma (MM) there is an urgent need to identify new markers with predictive value superior to the traditional clinical and histological parameters. Angiogenesis and lymphangiogenesis have been recognized as critical processes in tumour growth and metastasis development, and numerous studies have evaluated the significance of these parameters in predicting the prognosis in solid tumours, including MM. We set out to determine whether angiogenesis, lymphangiogenesis and lymphatic invasion (LI) are valuable prognostic markers in MM. We systematically reviewed the available literature and subsequently performed a meta-analysis on the compiled data. To be eligible for the systematic review, a study had to provide the microvessel density (MVD), the lymphatic vessel density (LVD) or information about LI, assessed by immunohistochemistry on the primary site in patients with MM. To be evaluable for the meta-analysis, a study also had to provide information on clinical outcome. We approached selected studies with the Reporting recommendations for tumour marker (REMARK) criteria, verifying whether they had followed the recommendations. In total, nine angiogenesis, seven lymphangiogenesis and 10 LI studies were included in our meta-analysis, representing 419, 474 and 802 patients, respectively. Using meta-analysis, we showed that peritumoral LVD and the presence of LI have prognostic value for patients with MM. In contrast, MVD and intratumoral LVD did not have prognostic value in these patients. LVD and LI seem to have prognostic value for patients with MM.

Impact of VEGF gene polymorphisms in elderly cancer patients: clinical outcome and toxicity

Vascular endothelial growth factors (VEGFs) are the key regulators in angiogenesis and have been shown to play a significant role in the progression and prognosis of angiogenesis-related diseases, such as cancer. VEGF inhibitors are a current pharmacological tumoral strategy. However, despite the strong association between aging and cancer incidence and progression, recent findings suggest impaired angiogenesis accompanied by a reduced expression of VEGF in cells derived from aging subjects. Specific variations of VEGF genes have been demonstrated to be genetic determinants for susceptibility, outcome and therapy response, especially for the solid tumors. Considering the complications present in frail elderly patients, analysis of VEGF genetic polymorphisms in these subjects may further help in tailoring an angiogenic pharmacological strategy, and in improving our ability to better understand prognosis during therapy-related to cancer.

Comprehensive analysis of vascular endothelial growth factor-C related factors in stomach cancer

BACKGROUND

Vascular endothelial growth factor-C (VEGF-C), which contributes to lymphatic metastasis (LM) in malignant disease, is one of the most important factors involved in physical and pathological lymphangiogenesis. Some VEGF-C related factors such as sine oculis homeobox homolog (SIX) 1, contactin (CNTN) 1 and dual specificity phosphatase (DUSP) 6 have been extensively studied in malignancies, but their expression levels and associations have still to be elucidated in stomach cancer.

METHODS

We detected their expression levels in 30 paired stomach cancer tissues using quantitative real-time reverse transcription-PCR (qRT-PCR). The expression and clinical significance of each factor was analyzed using Wilcoxon signed rank sum test. The correlation among all the factors was performed by Spearman rank correlation analysis.

RESULTS

The results suggest that VEGF-C and CNTN1 are significantly correlated with tumor size, SIX1 with the age and CNTN1 also with the cTNM stage. There are significant correlations of expression levels among VEGF-C, SIX1, CNTN1 and DUSP6.

CONCLUSIONS

There exists an important regulatory crosstalk involving SIX1, VEGF-C, CNTN1 and DUSP6 in stomach cancer.

Combined targeting of TGF-β1 and integrin β3 impairs lymph node metastasis in a mouse model of non-small-cell lung cancer

Background

Transforming Growth Factor beta (TGF-β) acts as a tumor suppressor early in carcinogenesis but turns into tumor promoter in later disease stages. In fact, TGF-β is a known inducer of integrin expression by tumor cells which contributes to cancer metastatic spread and TGF-β inhibition has been shown to attenuate metastasis in mouse models. However, carcinoma cells often become refractory to TGF-β-mediated growth inhibition. Therefore identifying patients that may benefit from anti-TGF-β therapy requires careful selection.

Methods

We performed in vitro analysis of the effects of exposure to TGF-β in NSCLC cell chemotaxis and adhesion to lymphatic endothelial cells. We also studied in an orthotopic model of NSCLC the incidence of metastases to the lymph nodes after inhibition of TGF-β signaling, β3 integrin expression or both.

Results

We offer evidences of increased β3-integrin dependent NSCLC adhesion to lymphatic endothelium after TGF-β exposure. In vivo experiments show that targeting of TGF-β and β3 integrin significantly reduces the incidence of lymph node metastasis. Even more, blockade of β3 integrin expression in tumors that did not respond to TGF-β inhibition severely impaired the ability of the tumor to metastasize towards the lymph nodes.

Conclusion

These findings suggest that lung cancer tumors refractory to TGF-β monotherapy can be effectively treated using dual therapy that combines the inhibition of tumor cell adhesion to lymphatic vessels with stromal TGF-β inhibition.

PIK3CA mutations define favorable prognostic biomarkers in operable breast cancer: a systematic review and meta-analysis

Background

Mutations of the p110α catalytic subunit of phosphatidylinositol 3-kinase (PIK3CA) are among the most common genetic aberrations in human breast cancer. At present, controversy exists concerning the prognostic value of the mutations.

Methods

We performed a systematic review and meta-analysis to clarify the association between PIK3CA mutations and survival outcomes. A comprehensive, computerized literature search of PubMed, Web of Science databases, the Chinese Biomedical Literature Database, and Wangfang Data until August 27, 2013 was carried out. Eligible studies were included according to specific inclusion criteria. Pooled hazard ratio was estimated by using the fixed effects model or random effects model according to heterogeneity between studies.

Results

Eight eligible studies were included in the analysis, all of which were retrospective cohort studies. The overall meta-analysis demonstrated that the PIK3CA mutations were associated with better clinical outcomes (hazard ratio 0.72; 95% confidence interval: 0.57–0.91; P=0.006). None of the single studies materially altered the original results and no evidence of publication bias was found. Further subgroup analysis of mutations in exons 9 and 20 did not show statistical significance.

Conclusion

PIK3CA mutations in operable primary breast cancer indicate a good prognosis. Further studies should be conducted to investigate the effect of PIK3CA mutations on clinical outcomes in different histologic types, different molecular subtypes of breast cancer, and different exons of PIK3CA.

Distribution of podoplanin-positive tumor vessels predicts disease-specific survival of node-positive breast cancer patients treated with anthracyclines and/or taxanes

We analyzed survival of 102 invasive ductal, node positive breast cancer patients, treated with surgery and adjuvant chemotherapy (anthracyclines and/or taxanes) with relation to: (a) well-known clinicopathological parameters, (b) MIB-1 labeling index (LI), (c) the distribution of podoplanin-positive vessels (DPV), expression of: (d) basal markers, and (e) fascin. Lower progression risk was found for patients with tumors characterized by (i) pN1 + pN2, (ii) MIB-1LI ≤ 28%, (iii) lack of lymphatic vessels or high tumor DPV than for patients with pN3, MIB-1LI > 28%, low DPV, respectively. Cox multivariate analysis revealed that both pN3 and low DPV were negative prognostic indicators.

Lymphangiogenesis and lymphatic vessel remodelling in cancer

The generation of new lymphatic vessels through lymphangiogenesis and the remodelling of existing lymphatics are thought to be important steps in cancer metastasis. The past decade has been exciting in terms of research into the molecular and cellular biology of lymphatic vessels in cancer, and it has been shown that the molecular control of tumour lymphangiogenesis has similarities to that of tumour angiogenesis. Nevertheless, there are significant mechanistic differences between these biological processes. We are now developing a greater understanding of the specific roles of distinct lymphatic vessel subtypes in cancer, and this provides opportunities to improve diagnostic and therapeutic approaches that aim to restrict the progression of cancer.

Identification of microRNAs associated with lymphangiogenesis in human gastric cancer

PURPOSE

Lymphatic metastasis is a primary cause of gastric cancer-related death, yet factors governing tumor cell lymphatic metastasis have not been fully elucidated. MicroRNAs (miRNAs) are a recently discovered class of regulatory, non-coding RNAs, some of which are involved in gastric cancer progression. However, little is known about which miRNA contributes to the lymphatic metastasis in human gastric cancer. This prompted us to find the significant miRNAs associated with lymphangiogenesis in human gastric cancer.

METHODS

We screened vascular endothelial growth factor C (VEGF-C) expression in several gastric cancer cell lines as well as in the immortalized human gastric mucosal cell line GES-1, by real-time reverse transcriptase PCR (qRT-PCR). The gastric cancer cell lines MKN-45 and SGC-7901, which have commonly been cultured with human lymphatic endothelial cells (HLECs) in vitro, promoted tube formation of HLECs following transformation with a VEGF-C expression vector. Using microarrays, we identified a panel of differentially expressed miRNAs in HLECs that had been co-cultured with VEGF-C-transformed gastric cancer cells compared with non-transformed gastric cancer cells. A subset of miRNAs was further validated using qRT-PCR.

RESULTS

We found altered expression of miRNAs in HLECs co-cultured with lymphangiogenesis-inducing VEGF-C-transformed gastric cancer cells, with 47 up-regulated and 42 down-regulated miRNAs. These findings were confirmed by qRT-PCR of selected miRNAs. Furthermore, several miRNAs were differentially expressed in patients with positive lymphatic metastasis of the primary gastric tumor. Up-regulated miRNAs included miR-648, miR-5002-3p, miR-4754, miR-4760-5p, miR-4491, miR-4252, miR-5007-3p, and miR-647; and down-regulated miRNAs included miR-3178, miR-593-5p, miR-4485, miR-135a-3p, miR-17, miR-1469, and miR-124-5p.

CONCLUSIONS

Several lymphangiogenesis-related miRNAs are significantly altered during lymphatic metastasis of gastric cancer.

Cytoplasmic HuR expression correlates with P-gp, HER-2 positivity, and poor outcome in breast cancer

HuR is an ubiquitously expressed RNA-binding protein that stabilizes messenger RNA and regulates translation. This protein has been shown to play an important role in carcinogenesis and cancer progression. P-glycoprotein (P-gp) is the product of the multidrug resistance 1 gene, and the overexpression of P-gp induces multidrug resistance and represents a major obstacle in cancer chemotherapy. The purpose of this study was to determine the expression of HuR and P-gp in human breast cancer tissues and analyze the relationship between HuR or P-gp expression and the clinical-pathological variables and patient outcomes. Immunohistochemistry was used to determine HuR and P-gp expression in 82 human breast cancer tissues and 20 matched adjacent noncancerous tissues. Additionally, 16 benign breast tumor samples were used as controls. The overexpression of cytoplasmic HuR was found in breast cancer but not in the matched adjacent noncancerous tissues or benign breast tumors. The expression levels of cytoplasmic HuR were significantly associated with increased age, high nuclear grade, and the positive expression of the ER, PR, and HER-2/neu. HuR was also associated with the expression of P-gp protein. Furthermore, univariate analysis indicates that patients with high expression levels of cytoplasmic HuR or P-gp had significantly reduced survival compared to patients with low expression levels. A multivariate analysis showed that age at diagnosis, nuclear grade, and cytoplasmic HuR positivity were independent indicators for disease-free survival and overall survival in patients with breast cancer. In conclusion, cytoplasmic HuR expression detected by immunohistochemical staining is a negative prognostic indicator for survival in patients with breast cancer.