Vascular endothelial growth factor C and vascular endothelial growth factor receptor 3 expression in squamous cell carcinomas of the head and neck

The role of VEGF-C/D and Flt-4 in the lymphatic metastasis of early-stage invasive cervical carcinoma

BACKGROUND

To investigate the role of vascular endothelial growth factors (VEGF)-C/D and their receptor Flt-4 in the lymphatic metastasis of early-stage invasive cervical carcinoma.

METHODS

Immunohistochemical (IHC) staining with the antibodies against VEGF-C, VEGF-D, and Flt-4 was used to examine the expression of them in 97 cases of early-stage cervical carcinoma (Ia-IIa). Meanwhile, the lymphatic vessel density (LVD) was measured using the antibody against lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1). We then analyzed the correlation between Flt-4-positive vessel density (FVD), LVD and clinicopathological features of the tumors.

RESULTS

(1) The positive rates of VEGF-C, VEGF-D, and Flt-4 were 57.7%, 60.8%, and 52.6% in the cervical tumor samples, respectively. (2) The expression levels of VEGF-C, VEGF-D, and Flt-4 were significantly correlated with lymphatic metastasis and lymphatic vessel invasion. LVD was significantly associated with lymph node metastasis and lymphatic vessel invasion. On the other hand, FVD was strongly associated with clinical staging. (3) The expression levels of VEGF-C and VEGF-D were significantly correlated with LVD and FVD, while Flt-4 levels showed no correlation with LVD or FVD.

CONCLUSION

VEGF-C/D and Flt-4 may play an important role in the process of lymphatic metastasis of early-stage invasive cervical carcinoma through paracrine and autocrine mechanisms.

EGFR inhibition as a therapy for head and neck squamous cell carcinoma

BACKGROUND

Improved understanding of disease biology of head and neck squamous cell carcinoma (HNSCC) with nearly universal expression of EGFR has led to the introduction of targeted therapies to interrupt signalling of this negative prognostic marker.

OBJECTIVE

We performed a literature review on the mechanisms and efficacy of anti-EGFR antibodies and EGFR tyrosine kinase inhibitors in patients with locally advanced or recurrent/metastatic HNSCC.

RESULTS/CONCLUSION

Clinical trials in HNSCC have administered EGFR directed drugs as single agents, in combination with chemotherapy or radiotherapy and demonstrated a good safety profile with antitumour activity in a subgroup of patients. The biology of responsiveness is still unclear, although there is growing evidence of an association of skin toxicity or presence of shorter EGFR intron 1 cytosine-adenine repeats with positive outcome.

Targeting angiogenesis in head and neck cancer

Tumor angiogenesis is a hallmark of advanced cancers and an attractive treatment target in multiple solid tumors. In the past 5 years anti-angiogenic therapies have seen a rapid ascent into mainstream clinical practice. For head and neck cancer (HNC), definitive evidence in the form of a pivotal trial is still pending. Nevertheless, preclinical and early clinical data support a central role of angiogenesis for HNC: up to 90% of HNCs express angiogenic factors such as vascular endothelial growth factor (VEGF) and the respective receptors (VEGFR1-3), and multiple studies support the prognostic implications of angiogenic markers for this tumor. Contrary to concerns that anti-angiogenic therapies could increase hypoxia and thereby treatment resistance, anti-angiogenic therapies in preclinical models appear to overcome resistance and preclinically synergize with traditional therapies, eg, radiation. Clinical use of anti-angiogenic agents for HNC, including bevacizumab, sorafenib, sunitinib, and others, is currently limited to clinical trials, and several larger trials are still ongoing. Single-agent anti-angiogenic drugs so far have not shown activity in unselected HNC patients, with a response rate of less than 4% for the small molecule anti-angiogenics sorafenib and the investigational agent SU5416. On the other hand, combinations of anti-angiogenic drugs with other treatments (analogous to other solid tumors) appear promising; for example, the combination of bevacizumab with the EGFR inhibitor erlotinib showed a response rate of 14.6%. Studies of bevacizumab with chemotherapy (phase III Eastern Cooperative Oncology Group [ECOG] trial) and in combination with chemoradiation are currently ongoing. The side effect profile is comparable to what has been observed in other tumor types and include hypertension, proteinuria, and thrombotic and hemorrhagic events. With the intense research effort preclinically and clinically, and some encouraging early results, anti-angiogenic therapies and biomarkers appear to be poised to play an important role in the treatment of HNC in the near future.

Expression of vascular endothelial growth factor-C does not predict occult lymph-node metastasis in early oral squamous cell carcinoma

Strong vascular endothelial growth factor-C (VEGF-C) expression has been correlated to occurrence of lymph-node metastases in patients with oral squamous cell carcinoma (OSCC). The incidence of occult lymph-node metastasis remains a decisive factor in the prognosis of patients with early OSCC. The aim of this study was to evaluate VEGF-C expression as a predictor of occult lymph-node metastasis in OSCC. Eighty-seven patients with primary OSCC arising in the tongue or floor of mouth, clinically T1N0M0 or T2N0M0, with (pN+) and without (pN0) occult lymph-node metastases were analyzed for VEGF-C expression by malignant cells. Occult lymph-node metastases (pN+) were detected in 22% of the 64 patients who were submitted to elective neck dissection. No statistically significant difference was found between OSCC with and without occult lymph-node metastasis in regard to VEGF-C immunoexpression by malignant cells and clinicopathologic features. Independently of VEGF-C expression, lymph-node metastasis (pN+) was the most significant prognostic factor for overall survival of patients with OSCC (p=0.030). These findings indicate that isolated VEGF-C expression by malignant cells is not of predictive value for occult lymph-node metastasis in the early stages of OSCC.

Phase II Trial of Sorafenib in Patients With Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck or Nasopharyngeal Carcinoma

Purpose

To determine the efficacy and safety of single-agent sorafenib in patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) and nasopharyngeal carcinoma (NPC).

Patients and Methods

In this single-arm phase II trial, oral continuous sorafenib was administered in 28-day cycles. Patients had ≤ one line of chemotherapy for recurrent and/or metastatic disease, Eastern Cooperative Oncology Group performance status of ≤ 2, and adequate organ function. At the end of stage 1, efficacy criteria for further accrual were not met, but the study was amended to enroll an additional five patients for paired tumor biopsies.

Results

Twenty-seven and 26 patients were eligible for toxicity and efficacy evaluations, respectively. One patient (3.7%; 95% CI, 0.1% to 19.0%) achieved a partial response. Disease stabilization was maintained in 10 patients (37.0%; 95% CI, 22.4% to 61.2%). The median time to progression was 1.8 months (95% CI, 1.6 to 3.4 months), and median overall survival time was 4.2 months (95% CI, 3.6 to 8.7 months). Sorafenib was well tolerated with few grade 3 and no grade 4 toxicities. Biomarker analysis of paired tumor samples before and after treatment with sorafenib revealed a decrease of pERK in all five patients, with a decrease in Ki67 in four patients, consistent with a disruption of ERK signaling. The antiapoptotic protein Mcl-1 was downregulated in four patients, and there was also evidence of antiangiogenic activity.

Conclusion

Sorafenib was well tolerated and had modest anticancer activity comparable to monotherapy with other targeted agents in this group of patients. Further development in combination with radiation or other agents may be warranted.

Histopathological and lymphangiogenic parameters in relation to lymph node metastasis in early stage oral squamous cell carcinoma

PURPOSE

Lymph node metastasis from oral squamous cell carcinoma (SCC) correlates with a poor prognosis. Therefore, accurate assessment of lymph node status is crucial in treatment planning. Furthermore, prediction of delayed neck metastasis (DNM), especially in early stage tumors with a clinically negative (N0) neck, will determine the need for neck dissection or irradiation. In this study, we assess various clinical, histopathological and lymphangiogenic parameters in early stage oral SCC and their association with DNM.

MATERIALS AND METHODS

Clinical, histological, and immunohistochemical analyses were undertaken for 29 patients with T1N0M0 or T2N0M0 oral SCC affecting the tongue or floor of mouth and correlated with the development of DNM.

RESULTS

Tumor thickness, nuclear pleomorphism, pattern of invasion, and immunohistochemical expression of the lymphangiogenesis-associated molecules VEGFR-3 and VEGF-C were associated with DNM.

CONCLUSIONS

Analysis of these parameters may help to identify patients who would benefit from a neck dissection or irradiation by predicting the likelihood of lymph node metastasis.

The role of the VEGF-C/VEGFR-3 axis in cancer progression

Vascular endothelial growth factor (VEGF) receptor 3 (VEGFR-3) (also called VEGFR-3) is activated by its specific ligand, VEGF-C, which promotes cancer progression. The VEGF-C/VEGFR-3 axis is expressed not only by lymphatic endothelial cells but also by a variety of human tumour cells. Activation of the VEGF-C/VEGFR-3 axis in lymphatic endothelial cells can facilitate metastasis by increasing the formation of lymphatic vessels (lymphangiogenesis) within and around tumours. The VEGF-C/VEGFR-3 axis plays a critical role in leukaemic cell proliferation, survival, and resistance to chemotherapy. Moreover, activation of the VEGF-C/VEGFR-3 axis in several types of solid tumours enhances cancer cell mobility and invasion capabilities, promoting cancer cell metastasis. In this review, we discuss the novel function and molecular mechanism of the VEGF-C/VEGFR-3 axis in cancer progression.

Intratumoral Lymphatic Vessels and VEGF-C Expression Are Predictive Factors of Lymph Node Relapse in T1-T4 N0 Laryngopharyngeal Squamous Cell Carcinoma

BACKGROUND

The presence of intratumoral lymphatic vessels (ILVs) and the expression of vascular endothelial growth factor-C (VEGF-C) in tumour cells have been studied as markers of lymphangiogenesis in order to evaluate their role in metastatic dissemination in laryngopharyngeal squamous cell carcinoma.

METHODS

A retrospective study was performed in 76 patients of N0 laryngopharyngeal carcinoma. with variable tumour size (T1-T4), histological grade, and location (supraglottic, glottic and hypopharyngeal). The presence of ILVs, as revealed by the expression of PA2.26 antigen and VEGF-C expression, were determined by immunohistochemistry (IHC). Low-grade and high-grade lymphangiogenesis were defined by qualitative and quantitative criteria.

RESULTS

Multivariate analysis revealed low-grade ILV and VEGF-C expression to be associated respectively with 30.3- and 16.2-fold higher probabilities of cervical lymph node relapse (P = 0.005 and P = 0.032) and with 16.2- and 8.44-fold shorter disease-free survival (P = 0.009 and P = 0.045).

CONCLUSIONS

Low-grade ILV and VEGF-C expression are independent predictive factors of cervical lymph node relapse and shortening of time to relapse in N0 laryngopharyngeal carcinoma.

RalA regulates vascular endothelial growth factor-C (VEGF-C) synthesis in prostate cancer cells during androgen ablation

Prostate cancer mortality is primarily due to failure to cure patients with metastatic disease. In its early stages, prostate cancer growth is enhanced by androgens. As such, the primary therapy for advanced (locally extensive or metastatic) prostate cancer consists of androgen deprivation therapy by pharmacotherapeutic or surgical means. Eventually, the tumor recurs owing to a transition from androgen-dependence to a highly metastatic and androgen refractory (androgen depletion-independent) phenotype. As the detailed molecular mechanism underlying this transition to a more aggressive phenotype is poorly understood, it has been difficult to develop effective treatments for this advanced stage of the disease. We have previously reported an increase in vascular endothelial growth factor-C (VEGF-C) expression in human prostate cancer cells after androgen withdrawal. We have also shown increased expression of the androgen receptor co-activator BAG-1L by VEGF-C, suggesting the involvement of this growth factor in transactivation of the androgen receptor, even at low concentrations of androgen. In our present study, we show that androgen deprivation of human prostate carcinoma cells activates the small GTPase, RalA, a molecule important for human oncogenesis. RalA activation leads to VEGF-C upregulation. We also show that elevated levels of intracellular reactive oxygen species in prostate cancer cells under androgen-ablated conditions is the major inducer of RalA activation and VEGF-C synthesis.

Molecular markers of head and neck squamous cell carcinoma: promising signs in need of prospective evaluation

BACKGROUND

The aim of this article is to review recent developments in the biological understanding of head and neck squamous cell carcinomas.

METHODS AND RESULTS

We describe the markers according to their function and their prognostic or predictive roles. Some associations can be found between molecular markers and invasiveness, aggressiveness, degree of differentiation, and tumor stage, but only a few clinical studies have shown an impact on prognosis. In addition, despite an increasing number of articles relating to this topic, the small number of patients included in the studies reported reduces the clinical implications of these results. Few studies applied a more comprehensive molecular analysis approach, such as DNA microarrays or differential expression profiling by polymerase chain reaction, to identify a combination of markers that could be more informative than a single molecular marker.

CONCLUSION

Some progress has been made with respect to molecular markers and head and neck cancers. Translational and prospective, hypothesis-driven research must proceed with sufficient rigor to facilitate the clinical applicability of such results.

Expression of vascular endothelial growth factor-C and angiogenesis in esophageal squamous cell carcinoma

AIM: To investigate the expression of vascular endothelial growth factor-c (VEGF-C) mRNA and microvessel density (MVD) in human esophageal squamous cell carcinoma (ESCC) and its relationship with clinical significance.

METHODS: Specimens obtained from 43 patients undergoing surgical resection for ESCC were used in this study. The expression of VEGF-C mRNA was examined by in situ hybridization. Tumor MVD was determined immunohistochemically with anti-CD31 antibody and estimated by image analysis. Ten sections of adjacent normal mucosa were also examined.

RESULTS: VEGF-C mRNA expression was detected in cytoplasm of carcinoma cells. Of the 43 ESCC patients studied, 18 cases (41.9%) were positive for VEGF-C mRNA. No VEGF-C mRNA expression was observed in normal esophageal mucosa. VEGF-C mRNA expression correlated significantly with lymph node metastasis, TNM stage and depth of invasion (P < 0.05). Furthermore, histological grade (differentiation) tended to correlate with VEGF-C mRNA expression, but was not statistically significant (P > 0.05). In tumor lesions, the MVD was significantly greater than that in normal esophageal mucosa. MVD correlated significantly with lymph node metastasis, TNM stage and depth of invasion (P < 0.05), but not with histological grade (differentiation) (P > 0.05). Lesions with VEGF-C mRNA expression had a significantly higher MVD than that of those without VEGF-C mRNA expression (P < 0.05).

CONCLUSION: VEGF-C plays a role in lymphatic metastasis via lymphangiogenesis and angiogenesis in ESCC. VEGF-C is one of the important predictors of the biological behavior in ESCC.

The balance of VEGF-C and VEGFR-3 mRNA is a predictor of lymph node metastasis in non-small cell lung cancer

A positive association between vascular endothelial growth factor-C (VEGF-C) expression and lymph node metastasis has been reported in several cancers. However, the relationship of VEGF-C and lymph node metastasis in some cancers, including non-small cell lung cancer (NSCLC), is controversial. We evaluated the VEGF-C and vascular endothelial growth factor receptor-3 (VEGFR-3) expression in NSCLC samples from patients who had undergone surgery between 1998 and 2002 using real-time quantitative RT–PCR and immunohistochemical staining. We failed to find a positive association between VEGF-C and VEGFR-3 mRNA expression and lymph node metastasis in NSCLC. An immunohistological study demonstrated that VEGF-C was expressed not only in cancer cells, but also in macrophages in NSCLC, and that VEGFR-3 was expressed in cancer cells, macrophages, type II pneumocytes and lymph vessels. The VEGF-C/VEGFR-3 ratio of the node-positive group was significantly higher than that of the node-negative group. Immunohistochemical staining showed that VEGFR-3 was mainly expressed in cancer cells. The immunoreactivity of VEGF-C and VEGFR-3 was roughly correlated to the mRNA levels of VEGF-C and VEGFR-3 in real-time PCR. VEGF-C mRNA alone has no positive association with lymph node metastasis in NSCLC. The VEGF-C/VEGFR-3 ratio was positively associated with lymph node metastasis in NSCLC. This suggests that VEGF-C promotes lymph node metastasis while being influenced by the strength of the VEGF-C autocrine loop, and the VEGF-C/VEGFR-3 ratio can be a useful predictor of lymph node metastasis in NSCLC.

Cyclooxygenase-2 expression is associated with VEGF-C and lymph node metastases in gastric cancer patients

Previous studies have suggested that cyclooxygenase-2 (COX-2) over-expression is associated with angiogenesis in gastric cancer. However, the relationship between COX-2 and lymphangiogenesis is still unclear. The aim of this study was to determine the relationship between COX-2 expression and lymphangiogenic factor, vascular endothelial growth factor-C (VEGF-C), in human gastric cancer, as well as to correlate with clinicopathological parameters. Sixty-three gastric cancer patients underwent radical gastrectomy (D2 or D3) were enrolled in this study. The expression of COX-2 and VEGF-C were detected by immunohistochemistry, and the small lymphatic vessels were immunohistochemically stained by LYVE-1 antibody. The association between COX-2 and VEGF-C expressions and clinicopathological parameters (such as gender, tumor location, lymph node status and Lauren classification) were determined. VEGF-C over-expression was observed in 33 of 63 patients (52%), while COX-2 over-expression occurred in 42 of 63 tumor samples (67%). Presence of microlymphatic vessels with LYVE-1 staining was found in 35 cases. COX-2 over-expression was highly correlated with VEGF-C over-expression (P = 0.032), microlymphatic vessels (P = 0.002) as well as presence of metastatic lymph nodes (P = 0.007). However, no significant correlation was found between COX-2 expression and other clinicopathological parameters. Our data suggest that COX-2 expression is associated with lymphangiogenesis and lymph node metastasis in human gastric carcinoma. This raises the possibility that COX-2-mediated VEGF-C over-expression might promote lymph node metastasis via lymphangiogenesis pathway in patients with gastric cancer.

Inducible nitric oxide synthase activity correlates with lymphangiogenesis and vascular endothelial growth factor-C expression in head and neck squamous cell carcinoma

Nitric oxide (NO) is a diatomic free radical molecule that has been implicated in tumour angiogenesis and progression of head and neck squamous cell carcinoma (HNSCC). However, the mechanism underlying the effect of NO on tumour spread remains largely unknown. Tumour lymphangiogenesis has recently received considerable attention and there is increasing evidence that it is relevant for metastasis to lymph nodes in HNSCC. Here, we study the correlation between inducible NOS synthase (iNOS) activity and lymphangiogenesis in a series of 60 HNSCCs and the possible involvement of the lymphangiogenic factor vascular endothelial growth factor (VEGF)-C. HNSCC presenting with lymph node metastasis had a significantly higher lymphatic vessel density in both the tumour mass and the peritumour area (p = 0.006 and p = 0.001, respectively). Similarly, tumours with lymph node metastasis showed greater lymphatic vessel area than tumours with no lymph node involvement (p = 0.001 for intratumour lymphatics and p < 0.001 for peritumour lymphatics). iNOS activity measured in specimens from the tumour periphery correlated strongly with both lymphatic vessel density and lymphatic vessel area (p = 0.01, rs = 0.45 and p < 0.001, rs = 0.725, respectively). Conversely, these correlations were not observed in specimens from the tumour core. In addition, VEGF-C mRNA expression was significantly elevated in tumours with high iNOS activity (p = 0.008, rs = 0.563), and VEGF-C expression correlated positively with the presence of lymph node metastases (p = 0.03). In vitro, in the A431 human squamous carcinoma cell line, exogenous and endogenous stimulation of the iNOS pathway led to up-regulation of VEGF-C, which was blocked by the NOS inhibitor L-NNA. Taken together, our results indicate that iNOS activity may promote lymphangiogenesis and spread to lymph nodes in HNSCC, with the possible involvement of VEGF-C.

The VEGF-C/Flt-4 axis promotes invasion and metastasis of cancer cells

Flt-4, a VEGF receptor, is activated by its specific ligand, VEGF-C. The resultant signaling pathway promotes angiogenesis and/or lymphangiogenesis. This report provides evidence that the VEGF-C/Flt-4 axis enhances cancer cell mobility and invasiveness and contributes to the promotion of cancer cell metastasis. VEGF-C/Flt-4-mediated invasion and metastasis of cancer cells were found to require upregulation of the neural cell adhesion molecule contactin-1 through activation of the Src-p38 MAPK-C/EBP-dependent pathway. Examination of tumor tissues from various types of cancers revealed high levels of Flt-4 and VEGF-C expression that correlated closely with clinical metastasis and patient survival. The VEGF-C/Flt-4 axis, through upregulation of contactin-1, may regulate the invasive capacity in different types of cancer cells.

Tumor-induced lymphangiogenesis: a target for cancer therapy?

Recent advances in understanding the biology of lymphangiogenesis, the new growth of lymphatic vessels, have cast new light on the molecular basis of metastasis to regional lymph nodes. The receptor tyrosine kinase VEGFR-3 is virtually exclusively expressed on lymphatic but not blood endothelium in the adult, and activation of VEGFR-3 by its ligands VEGF-C and VEGF-D is sufficient to induce lymphangiogenesis. Correlative studies with human tumors and functional studies using animal tumor models show that increased levels of VEGF-C or VEGF-D in tumors lead to enhanced numbers of lymphatic vessels in the vicinity of tumors, which in turn promotes metastasis to regional lymph nodes by providing a greater number of entry sites into the lymphatic system for invading tumor cells. These findings have prompted studies to investigate whether inhibitors of VEGFR-3 activation might represent novel therapeutic agents for the suppression of metastasis. However, a number of points regarding the therapeutic potential of anti-lymphangiogenic treatments in the context of cancer remain to be addressed. The spectrum and relative importance of molecules that induce lymphangiogenesis and the regulation of their expression during tumor progression, the reversibility of tumor-induced lymphangiogenesis, and possible side-effects of anti-lymphangiogenesis-based therapies all need to be investigated. Most importantly, the extent to which lymph node metastases contribute to the formation of metastases in other organs remains to be elucidated. These aspects are the focus of this review, and their investigation should serve as a roadmap to possible translational application.

Peritumoral lymphatic vessel density and vascular endothelial growth factor C expression in early-stage squamous cell carcinoma of the uterine cervix

PURPOSE

Lymphatic invasion and nodal metastasis plays a major role in the spread of cervical cancer; however, little is known about the mechanisms whereby tumor cells enter the lymphatic system.

EXPERIMENTAL DESIGN

We examined the intra- and peritumoral lymphatic vessel density (LVD) using D2-40 immunohistochemistry in 111 cervical squamous cell carcinomas and correlated them with vascular endothelial growth factor (VEGF)-C expression, clinicopathologic tumor features, and outcome.

RESULTS

Compared with benign cervix, intratumoral and peritumoral LVD was significantly increased (P < 0.0001). Peritumoral LVD was significantly higher than intratumoral LVD (P = 0.009). High peritumoral, but not intratumoral, LVD showed significant correlation with high tumor stage, lymphatic invasion, and nodal metastasis. VEGF-C showed increased expression at the invasive edge compared with the center of tumors (P < 0.0001) and correlated with high peritumoral LVD, lymphatic invasion, and nodal metastasis. High peritumoral LVD and VEGF-C expression at the invasive edge of tumors were associated with poor overall and recurrence-free survival in univariate analysis. In multivariate analysis, peritumoral LVD was the only independent term predictive of overall survival.

CONCLUSIONS

Our findings suggest a potential role for VEGF-C in tumor-induced lymphangiogenesis represented by high peritumoral LVD, which may be one of the mechanisms leading to lymphatic invasion and metastatic spread. High peritumoral LVD may be an independent prognostic factor in early-stage cervical cancer.

Mcl-1, vascular endothelial growth factor-R2, and 14-3-3sigma expression might predict primary response against radiotherapy and chemotherapy in patients with locally advanced squamous cell carcinomas of the head and neck

PURPOSE

This study was done to explore whether the expression of a selected set of proteins could predict primary response to radiotherapy or concomitant radiotherapy and chemotherapy in patients with advanced head and neck cancer.

EXPERIMENTAL DESIGN

Forty-three pretreatment tumor biopsies were taken during diagnostic panendoscopy and examined for Mcl-1, vascular endothelial growth factor (VEGF)-R2, CD9, and 14-3-3sigma expression by immunohistochemistry. Forty-three patients underwent primary radiotherapy, of which, 29 patients received concomitant chemotherapy (low dose daily cisplatin, mitomycin C bolus). The primary end-point was locoregional tumor control 6 months after completion of radiotherapy. Mcl-1, VEGF-R2, CD9, and 14-3-3sigma expression were correlated with patients' primary response to radiotherapy and chemotherapy and with established clinicopathologic variables.

RESULTS

Thirty complete and 13 partial responses were observed in our patient group. High expression levels of Mcl-1 (P=0.021), VEGF-R2 (P=0.032), and 14-3-3sigma (P=0.013), but not of CD9, in tumor biopsies was correlated with complete response. Overexpression of at least two of the three aforementioned proteins in pretreatment biopsies predicted-with a likelihood of 80%-whether a patient would achieve complete response to radiotherapy and chemotherapy. However, if only one of these proteins is overexpressed, there is a likelihood of 84.6% that this patient would not completely respond to therapy.

CONCLUSION

Determining the expression levels of Mcl-1, VEGF-R2, and 14-3-3sigma may be helpful in predicting the early clinical response in head and neck tumor patients receiving primary radiotherapy and chemotherapy and may further allow a pretherapeutic selection of patients.

Vascular endothelial growth factors and receptors in colorectal cancer: Implications for anti-angiogenic therapy

There are conflicting associations between growth factor expression and clinicopathological variables in colorectal cancer. This study aimed to define the expression of members of the VEGF family and the receptor, VEGFR2, in primary and metastatic sites of colorectal cancer and their relationship to metastatic potential. Thirty colorectal cancers, 12 lymph node metastases and 9 liver metastases were immunostained for VEGF-A, VEGF-C, VEGF-D and VEGFR2. VEGFR2 was expressed by endothelial cells and by the malignant epithelium. VEGF-C and VEGFR2 were co-expressed in the same territory and correlated throughout the primary tumour and in metastatic lymph nodes, but not in liver metastases. Their expression at the invasive tumour edge correlated with expression in metastatic nodes. The benefit of anti-VEGF antibodies might be increased by directing additional therapies against VEGF-C or against the kinase receptors to target redundancy in the system. A component of the therapeutic benefit might be due to a direct anti-tumour effect as well as an anti-angiogenic effect.

Proprotein convertases: "master switches" in the regulation of tumor growth and progression

Proprotein convertases (PCs) are a group of Ca2+-dependent serine proteases that have homology to the endoproteases subtilisin (bacteria) and kexin (yeast). This group is comprised of less than a dozen members, known as furin/PACE, PC1/PC3, PC2, PC4, PACE4, PC5/PC6, PC7/PC8/LPC, SKI/S1P, and NARC-1/PCSK9. Four PCs (Furin, PACE4, PC5, and PC7) have been localized to several different tissues and epithelial or nervous system tumors. PCs activate their cognate substrates by limited proteolysis at the consensus sequence RXR/KR downward arrow. Many PC substrates are well known cancer-associated proteins such as growth factors, growth factor receptors, integrins, and matrix metalloproteases (MMPs). For example, IGF-1 and its receptor, TGF-beta, VEGF-C, and MT-MMPs have direct roles in tumor progression and metastasis. Furin, a well-studied member of the PC family, has been associated with enhanced invasion and proliferation in head and neck, breast, and lung cancer. Conversely, inhibition of PC activity by PDX or several PC pro-segments, resulted in reduced processing of these key cancer-related substrates in human squamous cell carcinomas (SCC), colon adenocarcinoma, and astrocytoma cell lines. In parallel to these changes in cell proliferation and invasiveness as well as metastatic ability were markedly impaired. By controlling the maturation/activation of key cancer-associated proteins, PCs act as "master switches" at different levels during tumor development and progression. The manifold effects of PCs, influencing tumor cell proliferation, motility, adhesiveness, and invasiveness, should be exploited by further developing competitive/inhibitory therapeutic strategies that would be able to neutralize simultaneously the most salient cancer cell properties.

Flt-4-positive endothelial cell density and its clinical significance in non-small cell lung cancer

PURPOSE

Experimental studies have revealed that fms-like tyrosine kinase (Flt)-4 plays important roles in lymphangiogenesis in malignant tumors, but the clinical significance remains unclear. We assessed Flt-4 expression in tumor cells and in endothelial cells in correlation with clinical outcomes in non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

A total of 206 consecutive patients with resected pathological stage I-IIIA NSCLC were reviewed. Expression of Flt-4 was examined immunohistochemically, and Flt-4-positive microvessels were quantitatively evaluated (Flt-4-positive endothelial cell density).

RESULTS

There was no significant correlation between Flt-4-positive endothelial cell density and any characteristic of patients including nodal metastases. A significant correlation between Flt-4-positive endothelial cell density and Flt-4 status in tumor cells was documented (P < 0.001), but there was no significant difference in the mean Flt-4-positive endothelial cell density according to vascular endothelial growth factor-C or -D status in tumor cells. The 5-year survival rate for higher Flt-4-positive endothelial cell density tumor (56.4%) was significantly lower than that of lower Flt-4-positive endothelial cell density tumor (69.0%, P = 0.046); the prognostic significance was enhanced in pIIIA-N2 patients (5-year survival rates, 18.8% for higher Flt-4-positive endothelial cell density tumor and 50.0% for lower Flt-4-positive endothelial cell density tumor, respectively; P = 0.012). A multivariate analysis confirmed that higher Flt-4-positive endothelial cell density was a significant and independent prognostic factor (P = 0.019). CD34-positive vessel density or Flt-4 status in tumor cells was not a significant prognostic factor.

CONCLUSIONS

Flt-4-positive endothelial cell density, not Flt-4 status in tumor cells, was a significant prognostic factor in NSCLC.

Prognostic significance of VEGF immunohistochemical expression and tumor angiogenesis in head and neck squamous cell carcinoma

PURPOSE

Tumor angiogenesis is crucial for both the growth of the primary tumor and the development of metastases. Among the factors causing tumor angiogenesis, vascular endothelial growth factor (VEGF) is considered as a leading candidate. We aimed to assess the prognostic significance of VEGF and tumor angiogenesis in head and neck squamous cell carcinoma (HNSCC).

METHODS

We performed a retrospective study of 69 patients with HNSCC, in order to investigate whether VEGF immunohistochemical expression and tumor angiogenesis correlate with clinicopathological parameters and outcome. Tumor angiogenesis was estimated by determining microvessel density (MVD), and VEGF expression was assessed quantitatively.

RESULTS

Vascular endothelial growth factor and MVD correlated statistically significant with the clinical stage, but not with the presence of lymph node metastasis at the time of diagnosis. Tumors located in the oral cavity and larynx more often expressed high VEGF immunostaining compared with tumors located in the lower lip. High VEGF expression was associated with higher clinical stage and worse overall survival in this cohort of patients.

CONCLUSIONS

Vascular endothelial growth factor expression may have prognostic significance for patients with HNSCC.

Human Carcinoma Cell Growth and Invasiveness Is Impaired by the Propeptide of the Ubiquitous Proprotein Convertase Furin

Furin, a potent proprotein convertase involved in activation of several cancer-related substrates, is synthesized as an inactive zymogen, thus minimizing the occurrence of premature enzymatic activity that would lead to inappropriate protein activation or degradation. This natural inhibitory mechanism is based on the presence of an inactivating prosegment at the NH2 terminal of the zymogen. After initial autocatalytic cleavage, the prosegment remains tightly associated with the convertase until it reaches the trans-Golgi network where the dissociation of the prosegment and activation of furin occurs. We hypothesized that the inhibitory properties of the preprosegment of furin (ppFur) could be beneficial if ectopically expressed in tumor cells. Transfection of four human head and neck squamous cell carcinoma cell lines with the complete ppFur cDNA sequence (pIRES-EGFP-ppFur) or with the empty expression vector (pIRES-EGFP) was done. The inhibitory effect was evaluated using in vivo tumorigenicity, invasion, anchorage-independent growth in soft agar, and proliferation assays, as well as by investigating impairment of furin substrates processing. Following transfection of ppFur, a significant reduction in cell proliferation, tumorigenicity, and invasiveness was observed in vitro and in vivo. These biological changes are directly related to the inhibition of furin-mediated activation of crucial cancer-related substrates, such as membrane type 1 matrix metalloproteinase, transforming growth factor-beta, insulin-like growth factor-1 receptor, and vascular endothelial growth factor-C. PpFur expression in head and neck squamous cell carcinoma cell lines showed a mechanistic link between furin inhibition, decreased substrate processing, cell proliferation, and invasive ability. These findings suggest that furin inhibition is a feasible approach to ameliorate and even abolish the malignant phenotype of various malignancies.

Upregulation of VEGF-C by androgen depletion: the involvement of IGF-IR-FOXO pathway

Androgen ablation therapy is eventually followed by a more metastatic and androgen-refractory stage of prostate cancer. The detailed molecular mechanism of this gradual transition is not clearly understood. Recent reports correlate the high abundance of vascular endothelial growth factor-C (VEGF-C) to the lymph node metastasis seen in human prostate cancer (Tsurusaki et al., 1999). In this study, we report that androgen ablation in LNCaP cells augment the transcriptional upregulation of VEGF-C and the downregulation of the IGF-IR pathway, due to androgen withdrawal, is a potential mechanism for this observed VEGF-C transcription. Forkhead transcription factor FOXO-1, activated by SIRT-1, was identified as the downstream molecule within this pathway. Furthermore, the VEGF-C-induced increase of Bag-IL expression in LNCaP cells suggests that VEGF-C plays a role in the androgen-independent reactivation of the androgen receptor, resulting in androgen-refractory prostate cancer growth.

Potential autocrine function of vascular endothelial growth factor in head and neck cancer via vascular endothelial growth factor receptor-2

Vascular endothelial growth factor is a peptide with well-defined actions on the vasculature and fundamental role in tumor angiogenesis. Its action in vascular endothelium is exerted in a paracrine manner. The immunohistochemical expression of this protein by cancer cells in head and neck squamous cell carcinoma was correlated with increased tumor aggressiveness and poor survival in previous studies. In the past years, an increasing amount of studies demonstrated potential autocrine action of vascular endothelial growth factor in various neoplasms. However, the existence and the impact of such autocrine action in head and neck cancer have not been demonstrated yet. In this retrospective study, we evaluated the expression of vascular endothelial growth factor and its receptors in neoplastic cells, in a cohort of patients with head and neck squamous cell carcinoma, and compared this expression with tumor aggressiveness, clinicopathologic parameters and outcome. High expression of vascular endothelial growth factor was strongly correlated with high expression of vascular endothelial growth factor receptor-2 (but not vascular endothelial growth factor receptor-1) on the cancer cells (P<0.001). The co-overexpression of both the protein and vascular endothelial growth factor receptor-2 was associated with higher tumor proliferation rate (P<0.001). The above co-overexpression also correlated with worse survival (log rank P<0.05) in patients with oral-larynx squamous cell carcinoma. Our results suggest that an autocrine vascular endothelial growth factor loop, mediated via vascular endothelial growth factor receptor-2, probably exists in head and neck squamous cell carcinoma. These observations support the hypothesis that the use of vascular endothelial growth factor receptor-2 inhibitors as adjuvant antiangiogenic therapy might have beneficial effects for these patients, by disrupting both paracrine (endothelial-dependent) and autocrine actions of vascular endothelial growth factor.

Endostatin inhibits lymph node metastasis by a down-regulation of the vascular endothelial growth factor C expression in tumor cells

Anti-angiogenic therapy is a newly developed treatment method for malignant tumors. Endostatin has an anti-angiogenetic effect. Endostatin has also been shown to block the growth and metastasis of various cancers through the vascular system. However, there have so far been few reports on the relationship between endostatin and lymph node metastasis. In this study, we investigated the relationship between endostatin and the inhibition of lymph node metastasis. We first made recombinant adenovirus which expressed endostatin gene (Ad-end), and then performed the following experiments. Our findings showed Ad-end to inhibit the proliferation and tube formation of endothelial cells in vitro. In addition, Ad-end inhibited the growth of a human oral squamous cell carcinoma cell line (SQUU-B) implanted subcutaneously in the right flank of nude mice and orthotopically in the tongue of nude mice, and Ad-end also inhibited lymph node metastasis in orthotopic implantation. The number of CD31-positive blood vessels and 5'-nase-positive lymphatic vessels around Ad-end-infected tumors in tongue lesions was significantly lower than that in the control group. The down-regulation of vascular endothelial growth factor C (VEGF-C) in Ad-end-infected SQUU-B cells was recognized by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. These findings suggested that endostatin inhibited lymphangiogenesis and lymph node metastasis by suppressing the production of VEGF-C in tumor cells.

Simultaneous expression of furin and vascular endothelial growth factor in human oral tongue squamous cell carcinoma progression

PURPOSE

Squamous cell carcinoma (SCC) of the tongue is a common malignancy of the oral cavity. Furin convertase activates several precursor matrix metalloproteinases involved in the degradation of the extracellular matrix. The pattern of expression of furin and vascular endothelial growth factor-C (VEGF-C), two key molecules in neoplasm development, was examined during the progression from normal epithelium to invasive SCC.

EXPERIMENTAL DESIGN

We evaluated furin and VEGF-C expression and microvessel density (MVD) by immunohistochemistry in human tongue sections harboring normal epithelium, dysplastic epithelium, and/or SCC. Sections from 46 glossectomy specimens were assessed for furin expression. A selected group of 15 cases, each containing normal epithelium, precursor lesions, and invasive SCC, were further studied for furin and VEGF-C expression and MVD quantification. We also evaluated the pattern of furin expression and VEGF-C processing by Western blot analysis in three SCC cell lines with different degrees of aggressiveness.

RESULTS

Furin and VEGF-C expression was notably higher in most precursor lesions and SCCs than in normal epithelia. Approximately 60% (n = 26) and 100% (n = 15) of the normal epithelia showed low-intensity staining for furin and VEGF-C, respectively. Intense staining for furin and VEGF-C was detected in approximately 80% (n = 34) and 100% (n = 15) of the SCCs, respectively. A significant correlation was seen between the expression of these two markers (Spearman's test, P < 0.00002). We found a statistically significant increase in MVD when either dysplasia (432 +/- 19.06; P < 0.05) or SCC (546 +/- 17.24) was compared with normal epithelium (315 +/- 17.27; P < 0.0001). SCC71, the most aggressive cell line analyzed, was the one with the highest furin expression. This cell line totally processed the VEGF-C proform, whereas the less aggressive line SCC9, exhibiting the least furin expression, did not. SCC15, of intermediate aggressiveness and furin expression, showed intermediate pro-VEGF-C processing.

CONCLUSIONS

These findings suggest that furin is a useful marker of tumor progression and is responsible for VEGF-C processing. This in turn would enhance angiogenesis, leading to increased MVD associated with preinvasive and invasive neoplasia.

Expression of vascular endothelial growth factor (VEGF)-C in preoperative biopsy specimens and metastatic foci of regional lymph nodes in submucosal gastric carcinoma

BACKGROUND: Vascular endothelial growth factor (VEGF)-C is implicated in lymphangiogenesis, however the exact role of VEGF-C in promoting lymphatic spread of cancer cells remains largely unknown. METHODS: The expression of VEGF-C was immunohistochemically determined in 97 endoscopic biopsy specimens from 46 patients with submucosal gastric carcinoma (SGC). Nodal metastases including micrometastasis and isolated tumor cells (ITC) were evaluated by immunohistochemical staining for cytokeratin in 1650 lymph nodes, and tumor cells in these metastatic nodes were also examined for VEGF-C expression. RESULTS: In biopsy samples, VEGF-C was positively detected in 21 (47%) patients. Metastases were identified in 46 (2.8%) nodes from 15 (33%) patients. Metastases were detected in 39 nodes by hematoxylin-eosin (H&E) staining and in additional 7 nodes as ITC by immunohistochemical staining. The rate of lymph node metastases was significantly correlated with VEGF-C expression in biopsy samples (p < 0.05). The positive and negative predictive values of VEGF-C in biopsy specimens for nodal metastasis were 44 %(10/21) and 80% (20/25), respectively. Among the 46 metastatic nodes, tumor cells in 29 (63%) nodes positive patients expressed VEGF-C, whereas those in 17 (37%) nodes did not. VEGF-C expression was high in macronodular foci in medullary areas, whereas more than half of ITC or micrometastasis located in peripheral sinus lacked the expression of VEGF-C. CONCLUSIONS: Despite the significant correlation, immunodetcetion of VEGF-C in endoscopic biopsy specimens could not accurately predict the nodal status, and thus cannot be applied for the decision of the treatment for SGC. VEGF-C may not be essential for lymphatic transport, but rather important to develop the macronodular lesion in metastatic nodes.

COX-2 expression correlates with VEGF-C and lymph node metastases in patients with head and neck squamous cell carcinoma

Recent observations suggest an implication of the cyclooxygenase-2 (COX-2) in tumor lymphangiogenesis through an upregulation of vascular endothelial growth factor-C expression. It is unknown whether this mechanism also acts in squamous cell carcinoma of the head and neck region. We performed a retrospective study of 70 patients with head and neck squamous cell carcinoma in order to investigate whether COX-2 immunohistochemical expression correlates with vascular endothelial growth factor-C expression. We also examined the association of the expression of these molecules with clinicopathologic parameters (especially lymph node status) and outcome for these patients. We performed immunostaining on formalin-fixed, paraffin-embedded tissue sections by the routine streptavidin-biotin peroxidase labeled procedure. Increased cyclooxygenase-2 expression was observed in 30 of the 68 tumor samples (44%), while high vascular endothelial growth factor-C expression occurred in 26 of the 68 tumor samples (38%). High expression of the two proteins was correlated with the presence of lymph node metastasis at the time of diagnosis, and the observed association was even stronger when there was overexpression for both the antibodies (P<0.001). High expression of vascular endothelial growth factor-C, but not of COX-2 was correlated with increased mortality in patients with oral-larynx squamous cell carcinoma. When multivariate Cox regression model was applied, the presence of lymph node metastasis at the time of diagnosis, combined with overexpression of both the antibodies, was the only independent prognostic factor for mortality of these patients. Our results suggest that a lymphangiogenic pathway, in which COX-2 overexpression stimulates vascular endothelial growth factor-C upregulation, probably exists in head and neck squamous cell carcinoma. Also, the predictive ability for mortality of regional lymph node metastasis can be improved with the combined evaluation of the immunohistochemical expression of these two proteins.

Lymphatic Vessel Density and Vascular Endothelial Growth Factor-C Expression Correlate with Malignant Behavior in Human Pancreatic Endocrine Tumors

Metastatic dissemination of tumor cells to regional lymph nodes is a common early feature of many human cancers including pancreatic adenocarcinoma. In contrast, lymph node metastasis is more variably observed in pancreatic endocrine tumors. The objective of this study was to assess the lymphatic system of human pancreatic endocrine tumors and correlate this to clinical behavior. Immunohistochemistry was performed using antibodies to two recently identified markers of lymphatic endothelium, namely, LYVE-1 and podoplanin, and to the lymphangiogenic factor vascular endothelial growth factor (VEGF)-C. As has been reported previously, we observed that in the normal pancreas, islets of Langerhans are devoid of intra-islet lymphatics, but that lymphatics are present in connective tissue in association with ducts and blood vessels. We found that both benign and malignant pancreatic endocrine tumors contain intratumoral lymphatic vessels. Lymphatic vessel density was related to the size of the tumor in benign tumors and to the presence of liver metastasis but not to lymph node metastasis in malignant tumors. VEGF-C was expressed in tumor cells: 4 of 19 (21%) benign tumors were positive, whereas 6 of 9 (67%) borderline tumors and 9 of 11 (82%) carcinomas were positive. These findings strongly suggest that lymphangiogenesis occurs in pancreatic endocrine tumors and that lymphatic invasion and the development of metastases are associated with VEGF-C expression.

Immunohistochemical expression of vascular endothelial growth factor correlates with positive surgical margins and recurrence in T1 and T2 squamous cell carcinoma (SCC) of the lower lip

Tumor angiogenesis is associated with tumor progression and aggressiveness in a number of malignancies, and vascular endothelial growth factor (VEGF) is considered as a leading candidate in this process. The aim of the present study was to investigate the role of VEGF immunohistochemical expression and tumor angiogenesis in predicting local recurrence in surgically treated lip SCC. We performed a retrospective analysis of 50 patients with lip SCC in order to investigate whether VEGF immunohistochemical expression and tumor angiogenesis correlate with clinicopathologic parameters and outcome. Tumor angiogenesis was estimated by determining microvessel density (MVD) with the use of CD34 antibody. Our results showed that VEGF was strongly correlated with tumor invasion towards the surgical margin. There was also a significant association of high VEGF expression with a higher incidence of local recurrence (p < 0.001). We suggest that VEGF expression may be used as an index to distinguish patients with higher risk of relapse.

Relationship between VEGF-C expression and lymph node metastasis and prognosis in large intestinal carcinoma

AIM: To explore the expression of endothelial growth factors C (VEGF-C) in large intestine carcinoma, and its relationship to clinicopathological features and prognosis.

METHODS: The expression of VEGF-C in 96 cases of large intestine carcinoma was detected by SP immunohistochemical technique and its relationship to clinicopathological features and prognosis were analysed.

RESULTS: The expression of VEGF-C was significantly higher in intratumoral tissue than that in normal mucosa(42/96 vs 19/96, P < 0.01). VEGF-C positive expression was significantly correlated with tumor differentiation, Dukes' stage, lymph node metastasis and prognosis in 96 cases of large intestine carcinoma (P < 0.01 or P < 0.05), but its relationship to age and gender of patient, size, site and depth of invasion of tumour and organ metastasis was not found (P>0.05). The expression of VEGF-C in metastatic lymph nodes was fairly consistent with that in the primary tumour (P < 0.01).

CONCLUSION: The overexpression of VEGF-C in large intestine carcinoma can develop lymph node metastasis by inducing lymphangiogenesis, and it may serve as one prognostic factor and guide the treatment.

Expression and significance of VEGF-C and FLT-4 in gastric cancer

AIM: To investigate the expression of pathological factors of VEGF-C and its receptor FLT-4 in primary gastric cancer and adjacent normal tissues.

METHODS: The expression of VEGF-C and FLT-4 was studied in 80 primary gastric cancers and adjacent normal tissues from the same patients by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immumohistochemistry.

RESULTS: Both primary gastric cancer and adjacent normal tissue could express VEGF-C and FLT-4, and FLT-4 expression was also detected in endothelial cells of stromal blood vessels and lymphatic vessels. There was a significant difference in expression of VEGF-C between primary tumor and adjacent normal tissue samples (P = 0.01), and a statistical correlation between VEGF-C and FLT-4 expression in tumors (P = 0.00886). With regard to VEGF-C expression, there was a significant difference between moderate-poor differential type and high differential type (P = 0.032), and a significant difference between positive and negative lymph node metastases (P = 0.024). However, there was no significant difference between positive and negative serosal invasions (P = 0.219).

CONCLUSION: VEGF-C and its receptor FLT-4 play a role in the development of gastric cancer, and the tumors with expression of VEGF-C and FLT-4 are more likely to have lymph node metastasis.