Expressions of COX-2 and VEGF-C in gastric cancer: correlations with lymphangiogenesis and prognostic implications

Effect of celecoxib plus standard chemotherapy on serum levels of vascular endothelial growth factor and cyclooxygenase-2 in patients with gastric cancer

Elevated serum levels of vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) are associated with poor prognosis in patients with gastric cancer. Little is known regarding the clinical benefits of combining celecoxib, a selective inhibitor of COX-2, with standard chemotherapy regimens for the treatment of gastric cancer patients. In this study, we investigated the effect of the combinatorial use of celecoxib with standard chemotherapy on the serum levels of VEGF and COX-2 in patients with gastric cancer. In our study, 80 patients with gastric cancer who underwent laparoscopic radical surgery were randomized into two groups, the combination [celecoxib plus standard oxaliplatin, leucovorin and 5-fluorouracil (FOLFOX4) chemotherapy, n=40] and the FOLFOX4 alone (n=40) groups. In the combination group, celecoxib was orally administered to the patients (400 mg, twice daily). The serum levels of VEGF and COX-2 were measured by ELISA prior to and following surgery. We detected no significant difference in the serum levels of VEGF and COX-2 between the combination and FOLFOX4 alone groups prior to chemotherapy (P>0.05). However, after 6 cycles of chemotherapy, there was a greater decrease in the serum levels of VEGF and COX-2 in the combination group compared to those in the FOLFOX4 group (P<0.01). In addition, the serum levels of VEGF and COX-2 were closely correlated in patients with gastric adenocarcinoma prior to treatment. Our data indicated that, when combined with standard chemotherapy, celecoxib may reduce the serum levels of VEGF and COX-2, suggesting that COX-2 inhibitors may be of therapeutic value through the inhibition of tumor angiogenesis and the prevention of recurrence or metastasis. Thus, celecoxib may be a useful adjuvant agent to standard chemotherapy in patients with advanced gastric cancer.

Role of cyclooxygenase-2 in gastric cancer development and progression

Although the incidence of gastric cancer has been declining in recent decades, it remains a major public health issue as the second leading cause of cancer death worldwide. In China, gastric cancer is still the main cause of death in patients with malignant tumors. Most patients are diagnosed at an advanced stage and mortality is high. Cyclooxygenase-2 (COX-2) is a rate-limiting enzyme in prostanoid synthesis and plays an important role in the development and progression of gastric cancer. The expression of COX-2 in gastric cancer is upregulated and its molecular mechanisms have been investigated. Helicobacter pylori infection, tumor suppressor gene mutation and the activation of nuclear factor-kappa B may be responsible for the elevated expression of COX-2 in gastric cancer. The mechanisms of COX-2 in the development and progression of gastric cancer are probably through promoting the proliferation of gastric cancer cells, while inhibiting apoptosis, assisting angiogenesis and lymphatic metastasis, and participating in cancer invasion and immunosuppression. This review is intended to discuss, comment and summarize recent research progress on the role of COX-2 in gastric cancer development and progression, and elucidate the molecular mechanisms which might be involved in the carcinogenesis.

Collaborative overexpression of matrix metalloproteinase-1 and vascular endothelial growth factor-C predicts adverse prognosis in patients with gliomas

BACKGROUND AND AIM

Matrix metalloproteinase-1 (MMP-1), a member of the MMP family of zinc-dependent endopeptidases, has been detected to be strongly expressed in gliomas with high tumor grade and to be correlated with increased tumor invasiveness. Vascular endothelial growth factor-C (VEGF-C), which is able to induce MMP-1 transcription, has been found to be upregulated in glioblastoma compared to low grade gliomas and non-neoplastic brain. The aim of the present study was to investigate the clinical significance of the co-expression of MMP-1 and VEGF-C in glioma patients on determining the prognosis.

METHODS

One hundred and sixteen glioma patients (26 World Health Organization (WHO) grade I, 30 WHO grade II, 30 WHO grade III, and 30 WHO grade IV) and 15 non-neoplastic brain specimens acquired from 15 patients undergoing surgery for epilepsy as control were collected. Immunohistochemistry was used to evaluate the expression of MMP-1 and VEGF-C in glioma and non-neoplastic brain tissues. The correlations of collaborative MMP-1 and VEGF-C expression with selected clinicopathologic parameters and clinical outcome of glioma patients were also assessed.

RESULTS

Both MMP-1 and VEGF-C expression were significantly higher in glioma tissues compared to non-neoplastic brain tissues (both P<0.001). Of 116 glioma patients, 68 (58.62%) overexpressed MMP-1 and VEGF-C simultaneously. In addition, combined MMP-1 and VEGF-C expression was significantly associated with WHO grade (P<0.001) and Karnofsky performance status (KPS) score (P=0.01). Moreover, glioma patients expressing both MMP-1 and VEGF-C exhibited markedly poorer overall survival (P<0.001). According to the multivariate analyses, collaborative overexpression of MMP-1 and VEGF-C was found to be an independent prognostic factor for overall survival (P=0.009).

CONCLUSIONS

Our data demonstrated for the first time that overexpression of both MMP-1 and VEGF-C may be an independent poor prognostic factor in gliomas, suggesting the interaction between MMP-1 and VEGF-C collaboratively stimulated advanced tumor progression and adverse outcome. Inhibiting both MMP-1 and VEGF-C could be a novel therapeutic approach for gliomas.

Prognostic value of vascular endothelial growth factor expression in resected gastric cancer

BACKGROUND AND AIMS

Vascular endothelial growth factor (VEGF) is a potential prognostic biomarker for patients with resected gastric cancer. However, its role remains controversial. The objective of this study was to conduct a systematic review and meta-analysis of published literature.

METHODS

Relevant literature was identified using Medline and survival data from published studies were collected following a methodological assessment. Quality assessment of eligible studies and meta-analysis of hazard ratio (HR) were performed to review the correlation of VEGF overexpression with survival and recurrence in patients with gastric cancer.

RESULTS

Our meta-analysis included 44 published studies with 4,794 resected patients. VEGF subtype for the prediction of overall survival (OS) included tissue VEGF (HR=2.13, 95% CI 1.71-2.65), circulating VEGF (HR=4.22, 95% CI 2.47-7.18), tissue VEGF-C (HR=2.21, 95% CI 1.58-3.09), tissue VEGF-D (HR=1.73, 95% CI 1.25-2.40). Subgroup analysis showed that HRs of tissue VEGF for OS were, 1.78 (95% CI 0.90-3.51) and 2.31 (95% CI 1.82-2.93) in non-Asians and Asians, respectively. The meta-analysis was also conducted for disease free survival (DFS) and disease specific survival (DSS).

CONCLUSION

Positive expression of tissue VEGF, circulating VEGF, VEGF-C and VEGF-D were all associated with poor prognosis in resected gastric cancer. However, VEGF demonstrated no significant prognostic value for non-Asian populations. Circulating VEGF may be better than tissue VEGF in predicting prognosis.

The effect of vascular endothelial growth factor in the progression of bladder cancer and diabetic retinopathy

Bladder cancer and diabetic retinopathy is a major public health and economical burden worldwide. Despite its high prevalence, the molecular mechanisms that induce or develop bladder carcinomas and diabetic retinopathy progression are poorly understood but it might be due to the disturbance in balance between angiogenic factors such as VEGF and antiangiogenic factors such as pigment epithelium derived growth factor. VEGF is one of the important survival factors for endothelial cells in the process of normal physiological and abnormal angiogenesis and induce the expression of antiapoptotic proteins in the endothelial cells. It is also the major initiator of angiogenesis in cancer and diabetic retinopathy, where it is up-regulated by oncogenic expression and different type of growth factors. The alteration in VEGF and VEGF receptors gene and overexpression, determines a diseases phenotype and ultimately the patient's clinical outcome. However, expressional and molecular studies were made on VEGF to understand the exact mechanism of action in the genesis and progression of bladder carcinoma and diabetic retinopathy , but still how VEGF mechanism involve in such type of disease progression are not well defined. Some other factors also play a significant role in the process of activation of VEGF pathways. Therefore, further detailed analysis via molecular and therapeutic is needed to know the exact mechanisms of VEGF in the angiogenesis pathway. The detection of these types of diseases at an early stage, predict how it will behave and act in response to treatment through regulation of VEGF pathways. The present review aimed to summarize the mechanism of alteration of VEGF gene pathways, which play a vital role in the development and progression of bladder cancer and diabetic retinopathy.

Elevated VEGF concentrations in ascites and serum predict adverse prognosis in ovarian cancer

OBJECTIVE

To evaluate if serum and ascites VEGF-C concentration could be used as prognostic markers in ovarian cancer.

MATERIALS AND METHODS

Serum and ascites VEGF-C were measured in 118 patients with ovarian cancer and 24 patients with benign gynaecological disease. ELISA method was employed to evaluate VEGF-C concentration.

RESULTS

Serum and ascites in ovarian cancer patients were higher than those in benign gynaecological disease (P < 0.0001). Serum VEGF-C and ascites VEGF-C were both correlated with FIGO stage, tumor grade, and lymph node metastasis (P < 0.05). Univariate analysis revealed that FIGO stage (P < 0.0001), tumor grade (P < 0.0001), lymph node metastasis (P < 0.0001), serum VEGF-C concentration (P = 0.0001), and ascites VEGF-C concentration (P < 0.0001) were significantly correlated with overall survival. Including these variables in a multivariate analysis revealed that VEGF-C concentrations in serum and ascites were independent predictors of shorter overall survival.

CONCLUSION

Elevated VEGF-C concentrations in serum and ascites can be seen as the novel, widely available independent predictors of shorter overall survival in ovarian cancer.

Serum vascular endothelial growth factor (VEGF-C) as a diagnostic and prognostic marker in patients with ovarian cancer

VEGF-C is regarded as one of the most efficient factors in regulating lymphangiogenesis. The aim of this study was to better understand the role of VEGF-C in the progression of ovarian cancer and to assess its diagnostic and prognostic significance. A total of 109 patients with ovarian cancer, 76 patients with benign ovarian diseases, and 50 healthy controls were recruited in this study. Serum levels of VEGF-C were determined by ELISA method. The results showed that serum levels of VEGF-C were significantly higher in the patients with ovarian cancer than those with benign ovarian diseases and healthy controls (P<0.01). Serum level of VEGF-C was correlated with FIGO stage, lymph node metastasis, tumor resectability, and survival of the patients (P<0.05). The areas of receiver operating curves of VEGF-C were higher than those of CA125 in different screening groups. Analysis using the Kaplan-meier method indicated that patients with high VEGF-C had significantly shorter overall survival time than those with low VEGF-C (P<0.0001). In a multivariate analysis along with clinical prognostic parameters, serum VEGF-C was identified as an independent adverse prognostic variable for overall survival. These results indicated that serum VEGF-C may be a clinically useful indicator for diagnostic and prognostic evaluation in ovarian cancer patients.

High density of peritumoral lymphatic vessels measured by D2-40/podoplanin and LYVE-1 expression in gastric cancer patients: an excellent prognostic indicator or a false friend?

BACKGROUND

One of the most important prognostic indicators in gastric cancer is the presence of metastases in lymph nodes. Even now, little is known about lymphangiogenesis in neoplastic tissue, and little is also known about the transmission of a neoplastic cell from the tumor mass into a lymphatic vessel.

METHODS

This study examined the relationships between the density of lymphatic vessels (LVD) stained immunohistochemically with lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) and D2-40 (podoplanin) antibodies, the expression of vascular endothelial growth factor (VEGF)-C/D, selected clinical and pathomorphological factors, and the 5-year overall survival of gastric cancer patients.

RESULTS

Statistical analysis showed no impact of increased intratumoral or peritumoral LVD on gastric cancer patient survival, irrespective of the protein used to stain lymphatic vessels. Analysis showed that the probability of overall survival was decreased in the cases with enhanced VEGF-D immunoreactivity (P = 0.0045).

CONCLUSION

The study showed that the studied markers cannot be used to determine the required extent of the surgical procedure, as they have no statistically significant correlation with the degree of progression of the cancer, the stage of the disease assessed according to the TNM 5th classification of malignant tumors, clinicopathological features, and patient survival. VEGF-D is the only marker that can be regarded as an unfavorable prognostic indicator for patients with advanced gastric cancer.

Survivin knockdown enhances gastric cancer cell sensitivity to radiation and chemotherapy in vitro and in nude mice

INTRODUCTION

The aim is to assess the effect of survivin knockdown on the radio- and chemosensitivity of gastric cancer cells in vitro and in nude mice.

METHODS

Survivin messenger RNA and protein were detected by semiquantitative reverse transcription-polymerase chain reaction and Western blot. Survivin and control small hairpin RNA (shRNA) expression constructed vectors were stably transfected into gastric cancer SGC7901 cells. The cells were in turn subjected to irradiation, cisplatin or fluorouracil (5-FU) treatment for colony formation, methyl-thiazolyl-tetrazolium cell viability and flow cytometry assays in vitro. An in vivo nude mouse xenograft assay was performed to assess the effects of Survivin knockdown on regulation of the sensitivity of SGC7901 cells to irradiation, cisplatin or 5-FU treatment.

RESULTS

Survivin shRNA markedly inhibited levels of survivin messenger RNA and protein in SGC7901 cells and significantly increased sensitivity of the tumor cells to radiation treatment, ie, the mean lethal and quasi-threshold doses in survivin shRNA-transfected cells were significantly lower than that of the negative control shRNA-transfected and parental cells. The same is true for cisplatin- and 5-FU-treated tumor cells, ie, colony formation and cell viability of the survivin-knocked down SGC7901 cells were reduced, while apoptosis was induced compared with the control cells. Furthermore, the xenograft assay showed survivin knockdown in SGC7901 cells suppressed tumor formation and growth compared with the controls.

CONCLUSIONS

Knockdown of survivin expression enhanced sensitivity of gastric cancer cells to radiation, cisplatin and 5-FU treatment in vitro and in nude mice. These results demonstrate that clinical trails are warranted of survivin shRNA as an adjuvant therapy for gastric cancer patients.

Molecular mechanisms of lymphatic metastasis in solid tumors of the gastrointestinal tract

Tumor cell dissemination from the primary tumor site to distant organs is one of the characteristic properties of malignant tumors and represents a crucial step in the progression of disease. Although the pattern of spread may vary in different types of carcinomas, dissemination via the lymphatic system represents a common event in metastasis. The extent of lymph node metastasis is one of the major determinants for the prognosis of patients with gastrointestinal carcinomas and guides the therapeutically management. During the last decades, significant attention has been given to the molecular mechanisms that control lymphatic metastasis. The process of lymphangiogenesis has come into the focus. Lymphangiogenesis, the formation of newly lymphatics, comprises a series of complex cellular events and is controlled by a balance between pro- and anti-lymphangiogenic signals. This article will briefly describe the lymphatic system and then provide an overview of the molecular players involved in tumor lymphangiogenesis.

Lymphangiogenesis in non-Hodgkin's lymphoma and its correlation with cyclooxygenase-2 and vascular endothelial growth factor-C

We aimed to investigate the correlations between lymphangiogenesis, cyclooxygenase (COX)-2 and vascular endothelial growth factor-C (VEGF-C) in non-Hodgkin's lymphoma (NHL) and their associations with the clinical parameters of patients. A total of 75 patients diagnosed with NHL were enrolled in this study. Of the 75 patients, 14 (18.7%) had low-grade and 61 (81.3%) had aggressive lymphoma. We examined the immunohistochemical expression of COX-2 and VEGF-C and estimated lymphangiogenesis by counting lymphatic vessels expressing lymph vessel endothelial hyaluronan receptor-1 (LYVE-1). Our results showed that lymphatic vessel density (LVD) was positive in 59.0% of the cases with aggressive morphology, while the LVD positive rate of indolent lymphoma was only 28.6% (P=0.039). Both COX-2 and VEGF-C were correlated with lymphangiogenesis (P=0.030 and 0.000, respectively). The expression levels of COX-2 and VEGF-C were significantly correlated (P=0.015). LVD, COX-2 and VEGF-C were not correlated with the gender, age, lactate dehydrogenase (LDH) levels, β2 microglobulin (β2M) levels, extranodal involvement, disease stage, B symptoms or international prognostic index of the patients. In conclusion, lymphangiogenesis was correlated with aggressive histology in NHL. COX-2 and VEGF-C are inducers of lymphangiogenesis and their expression levels were correlated in NHL.

Immunohistochemical biomarkers in gastric cancer research and management

Gastric cancer still represents a major health problem, despite a decrease in its incidence in the last years. Due to the social impact of gastric cancer (GC), there is a need for novel biomarkers in order to stratify patients into appropriate screening, surveillance, or treatment programs. Although histopathology remains the most reliable and less expensive method, numerous efforts have been made searching for novel biomarkers. In recent years, several molecules have been identified and tested for their clinical relevance in GC management. In this paper, we will focus on a well-known GC marker, whose determination is mandatory in GC, HER2, a marker whose correlation with prognosis is still controversial (VEGF-A) and a quite novel, unconventional marker, the ether-à-go-go-related gene 1 (hERG1). All these proteins can be easily detected with immunohistochemistry, a technique widely used both in diagnostic and research laboratories that represents a link between surgical and molecular pathology, basic science, and clinical medicine.

Prognostic significance of vascular endothelial growth factor immunohistochemical expression in gastric cancer: a meta-analysis

Vascular endothelial growth factor (VEGF) is considered as a prime mediator of angiogenesis, and has been implicated in carcinogenesis and metastasis. Various studies examined the relationship between VEGF protein overexpression with the clinical outcome in patients with gastric cancer, but yielded conflicting results. The prognostic significance of VEGF overexpression in gastric cancer remains controversial. Electronic databases updated to July 2011 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between VEGF overexpression and survival of patients with gastric cancer. Survival data were aggregated and quantitatively analyzed. We performed a meta-analysis of 30 studies (n = 3,999 patients) that evaluated the correlation between VEGF overexpression detected by immunohistochemistry and survival in patients with gastric cancer. Combined hazard ratios suggested that VEGF-A overexpression had an unfavorable impact on overall survival (OS) (HR [hazard ratio] = 1.49, 95 % CI [confidence interval]: 1.22-1.77) and disease free survival (DFS) (HR = 1.85, 95 % CI: 1.38-2.32) in patients with gastric cancer. However, VEGF-C overexpression did not significantly correlate with OS (HR = 1.24, 95 % CI: 0.92-1.56) or DFS (HR = 1.15, 95 % CI: 0.78-1.52). VEGF-D is an unfavorable indicator of OS (HR = 1.68, 95 % CI: 1.02-2.34) and DFS (HR = 1.88, 95 % CI: 1.07-2.70) in patients with gastric cancer. VEGF-A and VEGF-D overexpression indicated a poor prognosis for patients with gastric cancer. VEGF-C overexpression was not associated with poor prognosis in patients with gastric cancer. The prognostic value of VEGF on survival still needs further larger prospective trials to be confirmed.

CCR7 and VEGF-C: molecular indicator of lymphatic metastatic recurrence in pN0 esophageal squamous cell carcinoma after Ivor-Lewis esophagectomy?

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a malignant tumor with a high incidence of lymph node metastasis. This study was undertaken to investigate the expression of CCR7 and VEGF-C in pN0 ESCC and its relationship with lymphatic metastatic recurrence.

METHODS

The expression of CCR7 and VEGF-C was examined by RT-PCR and immunohistochemistry. The recurrence rates were calculated by the Kaplan-Meier method and their difference was determined by log rank analysis. Cox regression analysis was performed to determine the independent risk factors.

RESULTS

In 99 patients, CCR7 mRNA expression was observed in 42 patients with a 3 year recurrence rate of 57.1%; VEGF-C mRNA expression was observed in 52 patients with a 3 year recurrence rate of 53.8%; and coexpression of CCR7 mRNA and VEGF-C mRNA was observed in 22 patients with a 3 year recurrence of 63.6%. Neither CCR7 mRNA nor VEGF-C mRNA expression was observed in 27 patients with a 3 year recurrence rate of 22.2%. The recurrence rates of patients with positive expression of CCR7 mRNA and/or VEGF-C mRNA were significantly higher than in patients without expression of both CCR7 mRNA and VEGF-C mRNA. We achieved better concordance between RT-PCR and immunohistochemistry detection of both markers. The Cox regression analysis showed tumor T classification, positive expression of CCR7/VEGF-C mRNA, and positive expression of CCR7/VEGF-C protein in tumor tissues to be independent risk factors for 3 year recurrence.

CONCLUSIONS

Patients with positive expression of CCR7 and/or VEGF-C have a higher recurrence rate than patients without expression of both CCR7 and VEGF-C. CCR7 and VEGF-C may become molecular indicators of disease in patients vulnerable to lymphatic metastatic recurrence.

Role of Akt-mediated VEGF signaling pathway in lymphangiogenesis in gastric cancer

Tumor lymphangiogenesis plays a vital role in lymphatic metastasis of solid tumors and is an important index for evaluation of prognosis. However, due to the lack of understanding of lymphatic endothelium-specific factors and the limitation of detection techniques, the specific mechanisms of lymphatic metastasis and molecule pathways involved in tumor lymphangiogenesis are not well understood. Akt signal pathway is an important transduction pathway that is closely related with the occurrence, proliferation, anti-apoptosis and metastasis of tumors. It has been found that Akt signaling has a close relationship with VEGF signal pathway and mediates lymphatic metastasis or tumor lymphangiogenesis. This article will summarize the role of Akt-mediated VEGF signaling pathway in lymphangiogenesis in gastric cancer.

Tumor lymphangiogenesis as a potential therapeutic target

Metastasis the spread of cancer cells to distant organs, is the main cause of death for cancer patients. Metastasis is often mediated by lymphatic vessels that invade the primary tumor, and an early sign of metastasis is the presence of cancer cells in the regional lymph node (the first lymph node colonized by metastasizing cancer cells from a primary tumor). Understanding the interplay between tumorigenesis and lymphangiogenesis (the formation of lymphatic vessels associated with tumor growth) will provide us with new insights into mechanisms that modulate metastatic spread. In the long term, these insights will help to define new molecular targets that could be used to block lymphatic vessel-mediated metastasis and increase patient survival. Here, we review the molecular mechanisms of embryonic lymphangiogenesis and those that are recapitulated in tumor lymphangiogenesis, with a view to identifying potential targets for therapies designed to suppress tumor lymphangiogenesis and hence metastasis.

Modulation of lymphangiogenesis: a new target for aspirin and other nonsteroidal anti-inflammatory agents? A systematic review

Recent studies have implicated that lymphangiogenesis plays a role in the development of metastasis in experimental cancer models and in certain types of human tumors. Epidemiological and laboratory data suggest that non steroidal anti-inflammatory agents (NSAIDs) have antitumor activities, although the mechanisms have not been elucidated. This systematic review aimed to synthesize data on the effect of aspirin and other NSAIDs on lymphangiogenesis. In particular, an answer was attempted to be found for the following primary questions: Is there an effect of aspirin and NSAIDs on lymphangiogenesis? If yes, is this effect mediated through COX-II inhibition or through COX-II-independent mechanisms? Electronical databases were searched with the appropriate search terms for the period from 1966 up to and including February 2011. The few identified experimental trials indicated that aspirin and other NSAIDs inhibit lymphangiogenesis, with a potential decrease in metastatic spread, possibly through COX-II-dependent regulation of VEGF-C expression. COX-II-independent mechanisms of inhibition of lymphangiogenesis by salicylates and the other NSAIDs have not been investigated. Although further research validation is needed, this proposed effect of NSAIDs might have therapeutic implications in chemoprevention, adjuvant chemotherapy, and treatment of metastatic disease.

Roles of VEGF-C and Smad4 in the lymphangiogenesis, lymphatic metastasis, and prognosis in colon cancer

BACKGROUND/AIMS

We combined two different signal pathways on transforming growth factor β1 (TGF-β1)-Smad and vascular endothelial growth factor C (VEGF-C)/VEGF receptors for exploring changes in pathway members and their influence on lymphangiogenesis and clinicopathological features.

MATERIALS AND METHODS

Expression of TGF-β1, TGF-βRII, Smad4, VEGF-C, and VEGFR-3 was immunohistochemically evaluated in 147 colon cancer patients who were followed up for 5 years.

RESULTS

Lymphatic vessel density in colon cancer tissues was significantly higher than in normal colonic tissues. Smad4 expression negatively correlated with lymphatic vessel count and VEGF-C expression. VEGF-C expression positively correlated with lymphatic vessel count. Analysis using the Kaplan-Meier method indicated that patients with VEGF-C-positive tumors had significantly shorter overall survival and tumor-free survival time than those with VEGF-C-negative tumors. Patients with Smad4-negative tumors had significantly shorter overall survival and tumor-free survival time than those with Smad4-positive tumors.

CONCLUSIONS

Both Smad4 and VEGF-C are involved in lymphangiogenesis and lymphatic metastasis. Smad4 and VEGF-C expression may be clinically useful indicators for prognostic evaluation in colon cancer patients.

Gastric cancer: basic aspects

Gastric cancer (GC) is a world health burden, ranging as the second cause of cancer death worldwide. Etiologically, GC arises not only from the combined effects of environmental factors and susceptible genetic variants but also from the accumulation of genetic and epigenetic alterations. In the last years, molecular oncobiology studies brought to light a number of genes that are implicated in gastric carcinogenesis. This review is intended to focus on the recently described basic aspects that play key roles in the process of gastric carcinogenesis. Genetic variants of the genes IL-10, IL-17, MUC1, MUC6, DNMT3B, SMAD4, and SERPINE1 have been reported to modify the risk of developing GC. Several genes have been newly associated with gastric carcinogenesis, both through oncogenic activation (GSK3β, CD133, DSC2, P-Cadherin, CDH17, CD168, CD44, metalloproteinases MMP7 and MMP11, and a subset of miRNAs) and through tumor suppressor gene inactivation mechanisms (TFF1, PDX1, BCL2L10, XRCC, psiTPTE-HERV, HAI-2, GRIK2, and RUNX3). It also addressed the role of the inflammatory mediator cyclooxygenase-2 (COX-2) in the process of gastric carcinogenesis and its importance as a potential molecular target for therapy.