Japanese Journal of Clinical Oncology 33:21-27 (2003)
© 2003 Foundation for Promotion of Cancer Research
Expression of Vascular Endothelial Growth Factor C and D (VEGF-C and -D) is an Important Risk Factor for Lymphatic Metastasis in Undifferentiated Early Gastric Carcinoma
Department of Surgery, Division of Surgical Oncology, The University of Tokyo, Tokyo, Japan
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Background: Vascular endothelial growth factor C (VEGF-C) and D (VEGF-D) are considered to be potentially lymphangiogenic and can selectively induce hyperplasia of the lymphatic vasculature. In this study, we aimed to clarify the relation between expression of VEGF-C and -D and lymphatic metastasis in early gastric cancers.
Methods: Using the specific antibodies, we classified 105 cases which were treated as gastrectomy with standard lymphadenectomy at the First Department of Surgery, Tokyo University Hospital, between 1994 and 2001, into three groups (diffuse type, focal type and negative type) for VEGF-C and two groups (positive and negative) for VEGF-D.
Results: There was a significant correlation between the expression of VEGF-C and -D and lymphatic invasion but not with venous invasion. All of the 22 cases that were negative for VEGF-C and -D were histologically classified as adenocarcinoma of undifferentiated type and showed negative lymph node metastasis and also negative lymphatic invasion. VEGF-C was positive in all tumors of differentiated type, while its expression varied in tumors of undifferentiated type. The VEGF-D positive rate is much lower than that of VEGF-C. In undifferentiated tumors in particular, VEGF-D was positive only in 4/64 (6%) and three of these four had nodal metastasis. Therefore, in tumors of differentiated type, expression of VEGF-C and -D had no clinical relevance. In tumors of undifferentiated type, the negative expression of VEGF-C suggests lack of nodal metastasis, while the positive expression of VEGF-D suggests nodal metastasis. The lymph node metastasis was significantly related to the expression of VEGF-C and -D in adenocarcinomas of undifferentiated type but not in those of differentiated tumors.
Conclusions: In early gastric cancers of histologically undifferentiated type with negative expression of VEGF-C and -D, limited surgery might be safely applied because the possibility of nodal metastasis is very low. These observations are based only on retrospective analysis of a small case series and further evaluation with a larger number of cases is necessary.
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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The incidence of early gastric carcinoma (EGC), defined as being confined to the mucosa (intramucosal carcinoma; M) or submucosa (submucosal carcinoma; SM), had increased by the end of the 20th century. Since these early cancers are rarely accompanied by metastasis, a partial excision of stomach or endoscopic mucosal resection (EMR) have frequently come to be performed in order to maintain the postoperative quality of life. As a whole, lymph node metastasis is observed in 2–4% of M carcinoma and in 10–15% of SM carcinoma (1,2). For other patients without lymph node metastasis, conventional gastrectomy with lympadenectomy can be avoided. To establish the safety of surgical resection, factors that could predict lymph node metastasis have been sought, such as tumor size, invasion depth, macroscopic appearance and histological differentiation (3). From other reports, early gastric carcinoma which satisfy the following criteria are unlikely to metastasize to lymph nodes: (i) confined to the mucosa; (ii) <1.5 cm in diameter; (iii) macroscopically elevated; (iv) macroscopically depressed, without intramural ulcers or ulcer scars (endoscopically no fold convergence); and (v) histologically differentiated (4,5). However, there are many node negative cases that do not satisfy the above criteria.
VEGF-C is a member of the VEGF family of highly glycosylated growth factors that regulate vasculogenesis, hematopoiesis, angiogenesis, lymphangiogenesis and vascular permeability and are implicated in many physiological and pathological processes (6,7). In the skin of transgenic mice, overexpression of the VEGF-C cDNA has been shown to induce selectively lymphatic endothelial cell proliferation and hyperplasia of the lymphatic vasculature (8). Yanai et al. recently reported that VEGF-C transfected tumor cell line implanted into the stomachs of nude mice induced highly developed lymph node metastasis (9). VEGF-C binds to the tyrosine kinase receptor Flt-4, which has been renamed VEGFR-3. The distribution of VEGFR-3 is highly restricted to the lymphatic endothelial cells in adult (10,11).
The expression of VEGF-C was most prominently detected in human heart, placenta, muscle, ovary and small intestine (12) and is even higher in several types of human malignant tumors (13,14), including breast (15), lung (16), prostate (17) and colorectal carcinomas (17,18). In breast, lung and prostate, a positive correlation has been reported between the expression of VEGF-C and clinicopathological features, especially lymphatic factors. In gastric cancers, it has also been reported that expression of VEGF-C is well correlated with lymphatic invasion (19,20). Yonemura et al. have shown that VEGF-C expression significantly correlates with lymph node metastasis (19), while Kabashima et al. have reported that it has positive correlation only with lymphatic invasion but not with lymph node metastasis (20). Hence it is still controversial whether VEGF-C expression really reflects the nodal status in gastric cancer.
VEGF-D is another member that binds to VEGFR-3 (10,21). Because of its sequence similarity to VEGF-C, VEGF-D is thought to have similar biological effects. Stacker et al. reported that transfection of VEGF-D into 293 EBNA cells promotes the lymphatic metastasis in murine model (22). However, the expression of VEGF-D has not been extensively examined, although previous studies demonstrated that VEGF-D could be detected in certain neuroendocrine cells (23), melanoma (24) and colorectal carcinoma (25).
In this study, we used new antibodies to VEGF-C and -D with stricter specificity and examined whether the expression pattern of VEGF-C and -D can be a useful factor to predict the lymph node metastasis in early gastric carcinoma.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Materials
One hundred and five patients with early primary gastric carcinomas diagnosed and treated with curative gastrectomy with standard lymph node dissection at the First Department of Surgery, Tokyo University Hospital, between 1994 and 2001 were included in the study. In all cases, serial-step sections 3 mm wide were cut, fixed in 10% formalin solution, then embedded in paraffin. All the resected primary tumors and regional lymph nodes were histologically examined by hematoxylin–eosin staining according to the Japanese Classification of Gastric Carcinoma (26). All the lesions, even the minute ones, had invaded the mucosa and/or submucosa, but not beyond the muscularis propria. Tumors were histologically classified into two types based on the predominant features: differentiated type (well and moderately differentiated adenocarcinomas) and undifferentiated type (poorly differentiated adenocarcinoma and signet ring cell carcinoma). In addition, we examined several discrete histological parameters, including lymphatic invasion, venous invasion and lymph node metastasis.
Immunohistochemical Study of VEGF-C and -D
To evaluate the histological characteristics of the early gastric carcinomas with positive lymph node metastasis, we investigated the expression of VEGF-C and -D with immunohistochemical staining using affinity-purified goat polyclonal antibodies against VEGF-C (IBL, Fujioka, Japan) and VEGF-D (R&D System, Minneapolis, MN), respectively. Sections 3 µm thick were deparaffinized in xylene, hydrated through a graded series of ethanols, then immersed in 3% hydrogen peroxide in 100% methanol for 30 min to inhibit endogenous peroxidase activity. To activate the antigens, the sections were boiled in 10 mM citrate buffer pH 6.0 for 30 min. After being rinsed in phosphate-buffered saline (PBS), the sections were incubated with normal rabbit serum for 10 min and then incubated overnight at 4°C in humid chambers with the primary antibody to VEGF-C at 1:30 dilution or VEGF-D at 1:50 dilution. After washing three times with PBS, the sections were incubated with biotinylated rabbit anti-goat immunoglobulin for 20 min. After washing again with PBS, the slides were treated with peroxidase-conjugated streptavidin for 20 min and developed by immersion in 0.01% H2O2 and 0.05% diaminobenzidine tetrahydrochloride for 3 min. Light counterstaining with Mayer’s hematoxylin was performed.
Statistical Analysis
All statistical calculations were carried out using StatView-J 5.0 statistical software (SAS Institute, USA). The relationship between the depth of invasion and clinicopathological features, the relationship between venous invasion and expression of VEGF-C and the relationships between lymphatic metastasis and expression of VEGF-C were examined by Wilcoxon’s test. Student’s t-test was used to analyse VEGF-D data. Differences with a P value of 
0.05 were considered to be statistically significant.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Clinicopathological Features
The clinical and pathological characteristics of 105 patients are summarized in Table 1.
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Immunohistochemical Analyses
From the staining pattern of VEGF-C, the gastric carcinomas were divided into three categories. Many carcinoma cells were brightly stained in their cytoplasm. In some cases, however, none of the carcinoma cells in the entire sections showed significant reactivity, and were classified as the VEGF-C negative group (Fig. 1c). Other cases that showed positive staining in carcinoma cells were further divided into diffuse type and focal type by their staining pattern. In some cases, almost all carcinoma cells in each section (>98%) were homogeneously stained, and were classified as diffuse type (Fig. 1a). In other cases, both positive and negative cells co-existed in every gland in the cancer. In those cases, the percentage of total tumor cells that were immunoreactive was 37–64% and they could be clearly distinguished from the diffuse type. These cases were classified as focal type (Fig. 1b).
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The samples were also stained with anti-VEGF-D. Expression of VEGF-D was divided into negative and positive types. In all positive cases, carcinoma cells were equally stained and heterogeneity was not observed in any sample, which showed a clear contrast to VEGF-C (Fig. 1d). In negative cases, a few carcinoma cells were stained only faintly (Fig. 1e).
The relation of the expression patterns between VEGF-C and -D is presented in Table 2. Thirteen carcinomas that expressed VEGF-C diffusely also expressed VEGF-D diffusely, while the other 13 carcinomas were negative for VEGF-D. Of 57 cancers that focally expressed VEGF-C, nine cases (16%) were positive for VEGF-D. All of the 22 carcinomas that lacked expression of VEGF-C did not express VEGF-D either. Hence the expression of VEGF-C and -D is significantly different P < 0.001). It is noted that all 22 cases that were negative for VEGF-C and -D were histologically diagnosed as undifferentiated type.
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Relation Between the Expression of VEGF-C and Clinicopathological Data
The relation between clinicopathological data and the expression of VEGF-C is shown in Table 3. No significant difference in tumor size was observed among diffuse, focal and negative types. Interestingly, diffuse type was found in 26 of 80 male patients (33%), whereas none was found in 25 female patients. There was no significant difference between the expression of VEGF-C and the depth of tumor invasion. When the VEGF-C expression was compared with histological types, all well differentiated carcinomas showed positive staining, whereas 22 of 64 (34%) undifferentiated carcinomas showed negative staining. Moreover, the percentage of diffuse type is significantly higher in differentiated carcinomas (20/41, 51%) than in undifferentiated carcinomas (9.3%). Hence VEGF-C was expressed at a higher level in differentiated than in undifferentiated carcinomas. (P < 0.001). Lymphatic invasion was significantly higher in diffuse type (5/26, 19%) than in other types (focal 2/57, 4%; negative 0/22, 0%) (P < 0.01), whereas venous invasion did not show a significant difference. Lymph node metastasis was positive in 19% (5/26) and 15% (9/57) of diffuse and focal type, respectively, whereas none of 22 cases of negative type was associated with lymph node metastasis.
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Relation Between the Expression of VEGF-D and Clinicopathological Data
Table 4 shows the relation with VEGF-D expression. The expression of VEGF-D tended to be higher as the depth increased and this was statistically significant (P < 0.05). VEGF-D was expressed in 44% (18/41) of differentiated carcinomas, but only in 6.3% (4/64) of undifferentiated carcinomas (P < 0.0001). Significant differences were observed in lymphatic invasion and lymph node metastasis, but not in venous invasion. Lymphatic invasion and metastasis were observed in four (18%) and six (27%) of 22 positive cases, but only in three (3.6%) and eight (9.6%) of 83 VEGF-D negative cases, respectively (P < 0.05).
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Expression of VEGF-C and -D and Nodal Status in Early Gastric Cancers with Different Histology
Early gastric cancers were divided into six groups according to the expression pattern of VEGF-C and -D. As shown in Table 5, carcinomas focally positive for VEGF-C and positive for VEGF-D had a relatively high metastatic rate (44%). In contrast, none of the carcinomas that lacked the expression of VEGF-C and -D showed lymph node metastasis. Since those tumors were all of undifferentiated type, the rate of lymph node metastasis was evaluated in two different histological groups (Table 6). In differentiated carcinomas, the node positive rate did not show a statistically significant difference. However, in undifferentiated carcinomas, the expression of both VEGF-C and -D showed a strong correlation with nodal status; 33% (2/6) and 19% (7/36) showed metastasis in diffusely and focally VEGF-C positive cases, respectively, whereas none of the VEGF-C negative cases showed metastasis (P < 0.01). Furthermore, metastasis was observed in 75% (3/4) of VEGF-D positive cases, but in only 10% (6/60) of negative cases (P < 0.001).
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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The metastatic spread of tumor cells is responsible for the majority of cancer deaths. Clinical findings have long suggested that by providing a pathway for tumor cell dissemination, the tumor-associated lymphatic system is one of the key components of metastatic spread. It is unknown, however, whether pre-existing vessels are sufficient to serve this function or whether tumor cell dissemination requires de novo lymphatic formation (lymphangiogenesis) or an increase in lymphatic size. Lymphangiogenesis has traditionally been overshadowed by the greater emphasis placed on the blood vascular system (angiogenesis). This is due in part to the lack of identification of lymphangiogenic factors, and also suitable markers that distinguish blood from lymphatic vascular endothelium. Recently, VEGF-C and -D, members of the VEGF family of growth factors, have been identified as potent factors in stimulating lymphoangiogenesis through their receptor VEGFR-3.
Previous studies have demonstrated that increased expression of VEGF-C in primary tumors correlates with increased dissemination of tumor cells to regional lymph nodes in a variety of human carcinomas, including gastric cancer (13–20). In gastric cancers, the expression level of VEGF-C has been shown to be correlated with lymphatic invasion (19,20). However, it is controversial whether VEGF-C expression has a positive correlation with lymph node metastasis. In those studies, VEGF-C was detected using polyclonal antisera to VEGF-C and the cancers were divided into VEGF-C-negative and -positive groups (19) or high and low groups, according to the percentage of total cancer cells that were positive (20). In this study, we used another affinity-purified antibody to VEGF-C. This antibody detected two clear bands (31 and 21 kDa) by western blotting using three gastric cancer cell lines (MKN28, MKN45 and MKN78) (data not shown). This is compatible with previous studies (27,28) and suggests that the antibody appears to be highly specific for VEGF-C. With this antibody, we found that early gastric cancers can be clearly divided into negative and positive cases and the latter were further divided into diffuse and focal types. The expression of VEGF-D has not yet been satisfactory characterized with regard to protein level, although neuroendocrine cells, melanoma and colorectal carcinoma cells have been shown to express VEGF-D (23–25). We used the same monoclonal antibody to VEGF-D as used in these studies and found that some of the early gastric cancers expressed VEGF-D, although the ratio of positive cells was less than that for VEGF-C. White et al. (25) reported that VEGF-D is fairly expressed in colorectal carcinoma and also adenoma and non-cancerous mucosa and the expression pattern is significantly associated with lymphatic involvement and patient survival. Our study on early gastric cancer is mostly consistent with their results.
In lung cancer, Niki et al. (16) reported that mRNA level of VEGF-D was decreased in cancer tissue as compared with normal lung tissue and the tendency was more marked in node-positive cases. George et al. (18) also reported that VEGF-D mRNA was significantly lower in both polyps and colorectal cancers compared with normal colonic mucosa, whereas VEGF-A and -C were significantly raised in colorectal cancers. Our results, however, indicated that both the VEGF-D and -C levels were significantly correlated with lymphatic invasion. In those studies, the majority of the samples examined were from advanced cases, which may be the reason for this discrepancy.
Another important finding is that expression of both VEGF-C and -D was lower in undifferentiated than in differentiated cancers. This was not observed in two reports on gastric cancer (20,21) and the discrepancy appears to be caused by the difference in the specificity of the antibodies used. Furthermore, in the present study, we could detect a strong correlation between the expression of these endothelial growth factors and lymph node metastasis only in undifferentiated cancers and not in differentiated gastric cancers. In general, gastric carcinomas of undifferentiated type were associated with marked fibrosis but did not contain many vessels as compared with differentiated carcinomas (4). Therefore, undifferentiated carcinoma cells may require the formation of new lymphatic vessels for lymphatic spread more than differentiated carcinomas cells.
The question remains of whether the expression of VEGF-C and -D is actually correlated with the density of lymphatic vessels in these tumors. We could not evaluate the exact number of lymphatic vessel counts because of the lack of mAb to distinguish selectively the lymphatic vessels from microvascular vessels. However, VEGFR-3, which is the receptor for VEGF-C and -D, and also LYVE-1 (29) and podoplanin (30), have been reported to react specifically with the lymphatic endothelium. When such mAbs are available, the staining of these samples will give us a clear answer to these points.
From the clinical point of view, it is very important that 22 undifferentiated cancers (14 M, eight SM) that lacked expression of VEGF-C and -D were not associated with regional lymph node metastasis. This is in clear contrast to the fact that VEGF-C-positive undifferentiated gastric cancers had a relatively high rate of metastasis. Generally, undifferentiated gastric cancers are more liable to metastasize to lymph nodes and therefore are usually excluded from consideration for EMR or local excision, even in early cases (2,31,32). However, from our data, we propose the possibility that some of the undifferentiated early gastric cancers can be safely treated with such surgical resection if they are categorized as VEGF-C and -D negative. Since every gland showed a similar staining pattern for VEGF-C and -D in our cancer specimens, negative cancers can be preoperatively distinguished with a few biopsy specimens. A prospective study to explore the correlation between VEGF expression of the biopsy specimens and node metastasis is warranted.
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FOOTNOTES |
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+ For reprints and all correspondence: Makoto Ishikawa, Department of Surgical Oncology, Faculty of Medicine, The University of Tokyo, 7–3–1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. E-mail: makoto-ishi@umin.ac.jp
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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1 Sano T, Kobori O, Muto T. Lymph node metastasis from early gastric cancer: endoscopic resection of tumor. Br J Surg 1992;79:241–4.[Web of Science][Medline]
2 Gotoda T, Yanagisawa A, Sasako M, Ono H, Nakanishi Y, Shimoda T, et al. Incidence of lymph node metastasis from early gastric cancer: estimation with a large number of cases at two large centers. Gastric Cancer 2000;3:219–25.[CrossRef][Medline]
3 Nakamura K, Ueyama T, Yao T, Zhong X-X. Pathology and prognosis of gastric carcinoma. Cancer 1992;70:1030–7.[CrossRef][Web of Science][Medline]
4 Watanabe H, Jass JR, Sobin LH. International Histological Classification of Tumors. World Health Organization, 2nd ed. Berlin: Springer 1990.
5 Matsukuma A, Furusawa M, Tomoda H, Seo Y. A clinocopathological study of asymptomatic gastric cancer. Br J Cancer 1996;74:1647–50.[Web of Science][Medline]
6 Karkkainen MJ, Petrova TV. Vascular endothelial growth factor receptors in the regulation of angiogenesis and lymphangiogenesis. Oncogene 2000;19:5598–605.[CrossRef][Web of Science][Medline]
7 Enholm B, Paavonen K, Ristimaki A. Comparison of VEGF, VEGF-B, VEGF-C and Ang-1 mRNA regulation by serum, growth factors, oncoproteins and hypoxia. Oncogene 1997;14:2475–83.[CrossRef][Web of Science][Medline]
8 Jeltsch M, Kaipainen A, Joukov V. Hyperplasia of lymphatic vessels in VEGF-C transgenic mice. Science 1997;276:1423–5.
9 Yanai Y, Furuhata T, Kimura Y. Vascular endothelial growth factor C promotes human gastric carcinoma lymph node metastasis in mice. J Exp Clin Cancer Res 2001;20:419–28.[Web of Science][Medline]
10 Karkkainen MJ, Makinen T, Alitalo K. Lymphatic endothelium: a new frontier of metastasis research. Nature Cell Biol 2002;4:E2–E5.[CrossRef][Web of Science][Medline]
11 Witmer AN, van Blijswijk BC, Dai J, Hofman P, Partanen TA. VEGFR-3 in adult angiogenesis. J Pathol 2001;195:490–7.[CrossRef][Web of Science][Medline]
12 Joukov V, Pajusola K, Kaipainen A. A novel vascular endothelial growth factor, VEGF-C, is a ligand for the Flt4 (VEGFR-3) and KDR (VEGFR-2) receptor tyrosine kinases. EMBO J 1996;15:290–8.[Web of Science][Medline]
13 Salven P, Lymboussaki A, Heikkila P. Vascular endothelial growth factors VEGF-B and VEGF-C are expressed in human tumors. Am J Pathol 1998;153:103–8.
14 O-charoenrat P, Rhys-Evans P, Eccles SA. Expression of vascular endothelial growth factor family members in head and neck squamous cell carcinoma correlates with lymph node metastasis. Cancer 2001;92:556–65.[CrossRef][Web of Science][Medline]
15 Kurebayashi J, Otsuki T, Kunisue H, Mikami Y, Tanaka K, Yamamoto S, et al. Expression of vascular endothelial growth factor (VEGF) family members in breast cancer. Jpn J Cancer Res 1999;90:977–81.[CrossRef][Web of Science]
16 Niki T, Iba S, Tokunou M, Yamada T, Matsuno Y, Hirohashi S. Expression of vascular endothelial growth factor A, B, C and D and their relationships to lymph node status in lung adenocarcinoma. Clin Cancer Res 2000;6:2431–9.
17 Tsurusaki T, Kanda S, Sakai H. Vascular endothelial growth factor-C expression in human prostatic carcinoma and its relationship to lymph node metastasis. Br J Cancer 1999;80:309–13.[CrossRef][Web of Science][Medline]
18 George ML, Tutton MG, Janssen F, Arnaout A, Abulafi AM, Eccles SA, et al. VEGF-A, VEGF-C and VEGF-D in colorectal cancer progression. Neoplasia 2001;3:420–7.[CrossRef][Web of Science][Medline]
19 Yonemura Y, Endo Y, Fujita H, Fushida S, Ninomiya I, Bandou E, et al. Role of vascular endothelial growth factor C expression in the development of lymph node metastasis in gastric cancer. Clin Cancer Res 1999;5:1823–9.
20 Kabashima A, Maehara Y, Kakeji Y, Sugimachi K. Overexpression of vascular endothelial growth factor C is related to lymphogenous metastasis in early gastric carcinoma. Oncology 2001;60:146–50.[CrossRef][Web of Science][Medline]
21 Orlandini M, Marconcini L, Ferruzzi R, Oliviero S. Identification of a c-fos-induced gene that is related to the platelet-derived growth factor/vascular endothelial growth factor family. Proc Natl Acad Sci USA 1996;93:11675–80.
22 Stacker SA, Caesar C, Baldwin ME, Thornton GE, Williams RA, Prevo R, et al. VEGF-D promotes the metastatic spread of tumor cells via the lymphatics. Nature Med 2001;7:186–91.[CrossRef][Web of Science][Medline]
23 Partanen TA, Arola J, Saaristo A, Jussila L, Ora A, Miettinen M, et al. VEGF-C and VEGF-D expression in neuroendocrine cells and their receptor, VEGFR-3, in fenestrated blood vessels in human tissues. FASEB J 2000;14:2087–96.
24 Achen MG, Williams RA, Minekus MP, Thornton GE, Stenvers K, Rogers PA, et al. Localization of vascular endothelial growth factor-D in malignant melanoma suggests a role in tumour angiogenesis. J Pathol 2001;193:147–54.[CrossRef][Web of Science][Medline]
25 White JD, Hewett PW, Kosuge D, McCulloch T, Enholm BC, Carmichael J, et al. Vascular endothelial growth factor-D expression is an independent prognostic marker for survival in colorectal carcinoma. Clin Cancer Res 2002;62:1669–75.
26 Japanese Gastric Cancer Association. Japanese Classification of Gastric Carcinoma. 2nd English Edition. Gastric Cancer 1998;1:10–24.[Medline]
27 Joukov V, Pajusola K, Kaipainen A, Chilov D, Lahtinen I, Kukk E, et al. A novel vascular endothelial growth factor, VEGF-C, is a ligand for the Flt4 (VEGFR-3) and KDR (VEGFR-2) receptor tyrosine kinases [erratum]. EMBO J 1996;15:1751.[Web of Science][Medline]
28 Skobe M, Hawighorst T, Jackson DG, Prevo R, Janes L, Velasco P, et al. Induction of tumor lymphangiogenesis by VEGF-C promotes breast cancer metastasis. Nature Med 2001;7:192–8.[CrossRef][Web of Science][Medline]
29 Banerji S, Ni J, Wang SX, Clasper S, Su J, Tammi R, et al. LYVE-1, a new homologue of the CD44 glycoprotein, is a lymph-specific receptor for hyaluronan. J Cell Biol 1999;144:789–801.
30 Breiteneder-Geleff S, Soleiman A, Kowalski H, Horvat R, Amann G, Kriehuber E, et al. Angiosarcomas express mixed endothelial phenotypes of blood and lymphatic capillaries: podoplanin as a specific marker for lymphatic endothelium. Am J Pathol 1999;154:385–94.
31 Seto Y, Shimoyama S, Kitayama J, Mafune K, Kaminishi M, Aikou T, et al. Lymph node metastasis and preoperative diagnosis of depth of invasion in early gastric cancer. Gastric Cancer 2001;4:34–8.[CrossRef][Medline]
32 Kunisaki C, Shimada H, Nomura M, Akiyama H. Appropriate lymph node dissection for early gastric cancer based on lymph node metastasis. Surgery 2001;129:153–7.[CrossRef][Web of Science][Medline]
Received April 30, 2002; accepted October 21, 2002
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