Microvessel density and VEGF expression are prognostic factors in colorectal cancer. Meta-analysis of the literature

Irinotecan therapy and molecular targets in colorectal cancer: a systemic review

Irinotecan is the second line chemotherapy for advanced stage colorectal cancer (CRC) after failure of first line chemotherapy with oxaliplatin and 5-fluorouracil. The aim of this review is to analyse the data on irinotecan as second line chemotherapy for advanced CRC and the potential roles of the molecular markers, p53 and vascular endothelial growth factor (VEGF) in the management of advanced CRC. Thus, the English literature from 1980 to 2008 concerning irinotecan, p53, VEGF and CRC was reviewed. On review, Phase II and III clinical trials showed that irinotecan improves pain-free survival, quality of life, 1-year survival, progression-free survival and overall survival in advanced CRC. p53 and VEGF were expressed in CRC and had a predictive power of aggressive clinical behaviour in CRC. Irinotecan sensitizes p53 wild type, mutant and null cells to Fas-mediated cell apoptosis in CRC cells. Wild type p53 cells were more sensitive to irinotecan than mutated p53. Irinotecan has an anti-VEGF effect inhibiting endothelial cell proliferation, increasing apoptosis and reducing microvascular density which is only limited by irinotecan toxicity levels. To conclude, irinotecan improves the patient's quality of life and the survival rates of patients with advanced CRC. p53 and VEGF status of the patients' tumour is likely to affect the responsiveness of CRC to irinotecan. It is recommended that studies of the expression of these molecular markers in relation to chemo-responsiveness of irinotecan should be carried out for better management of patients with advanced CRC.

Correlation between the immunohistochemical expressions of MMP-1, MMP-7 and VEGF and prognostic factors in colorectal adenocarcinoma

PURPOSE: To analyze the expression of metalloproteinase-1, metalloproteinase-7 and vascular endothelial growth factor (VEGF) in colorectal adenocarcinoma, and to correlate these with the clinical-pathological prognostic factors. METHODS: Tumor tissue from 82 patients was fixed in formalin and embedded in paraffin blocks. These samples were analyzed by means of the streptavidin-biotin immunohistochemical method, using the tissue microarray technique. Marker positivity was evaluated using categorical scores that determined cutoff percentages of stained tumor cells. Protein tissue expression was correlated with the variables of degree of cell differentiation, staging, disease-free interval, recurrence, survival and specific mortality. The Fisher exact and Kaplan-Meier tests were used to assess associations between the markers and the study variables. The log-rank and Wilcoxon tests were used to assess the significance of differences between curves of disease-free interval and survival. RESULTS: All tumors were positive for metalloproteinase-1; 50 (61%) were positive and 32 (39%) were negative for metalloproteinase-7; and 60 (74.1%) were positive and 21 (25.9%) were negative for VEGF. Correlation of marker expression, both in groups and individually, did not show statistical significance in relation to the degree of cell differentiation, staging, disease-free interval, survival or specific mortality. Recurrence showed a statistically significant correlation with positive expression of the three markers, when analyzed as a group (p = 0.038). CONCLUSION: The associated expression of metalloproteinase-1, metalloproteinase-7 and VEGF in colorectal adenocarcinoma is related to the incidence of disease recurrence.

Enhancement patterns of pancreatic adenocarcinoma on conventional dynamic multi-detector row CT: Correlation with angiogenesis and fibrosis

AIM: To evaluate retrospectively the correlation between enhancement patterns on dynamic computed tomography (CT) and angiogenesis and fibrosis in pancreatic adenocarcinoma.

METHODS: Twenty-three patients with pancreatic adenocarcinoma underwent dynamic CT and tumor resection. In addition to the absolute and relative enhanced value that was calculated by subtracting the attenuation value on pre-contrast from those on contrast-enhanced CT in each phase, we defined one parameter, “tumor-aorta enhancement ratio”, which was calculated by dividing enhancement of pancreatic cancer by enhancement of abdominal aorta in each phase. These enhancement patterns were correlated with the level of vascular endothelial growth factor (VEGF), microvessel density (MVD), and extent of fibrosis.

RESULTS: The absolute enhanced value in the arterial phase correlated with the level of VEGF and MVD (P = 0.047, P = 0.001). The relative enhanced value in arterial phase and tumor-aorta enhancement ratio (arterial) correlated with MVD (P = 0.003, P = 0.022). Tumor-aorta enhancement ratio (arterial) correlated negatively with the extent of fibrosis (P = 0.004). The tumors with greater MVD and higher expression of VEGF tended to show high enhancement in the arterial dominant phase. On the other hand, the tumors with a larger amount of fibrosis showed a negative correlation with the grade of enhancement during the arterial phase.

CONCLUSION: Enhancement patterns on dynamic CT correlated with angiogenesis and may be modified by the extent of fibrosis.

High Ki67, Bax, and thymidylate synthase expression well correlates with response to chemoradiation therapy in locally advanced rectal cancers: proposal of a logistic model for prediction

Background:

Recently, preoperative chemoradiation therapy (CRT) for rectal cancer has been increasingly used as a neoadjuvant treatment. In the present study, the relation between histological response to CRT and immunohistochemical markers in biopsy specimens was investigated.

Methods:

Biopsy specimens from a total of 60 patients were collected before preoperative CRT with S-1 and irinotecan, and liniac 45 Gy. Immunohistochemical staining for Ki67, Mcm3, Bax, Bcl-2, ssDNA, Grp78, thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), CD34, vascular endothelial growth factor, nestin, and L-type amino-acid transporter 1 was performed to allow comparison of the Ki67 labelling index (LI), Bax score, TS score, DPD score, microvessel density by CD34, and Grp78 score with cancer regression.

Results:

When the cases were divided into responders (Dworak grades 3 and 4) and non-responders (grades 1 and 2) groups, good correlations were evident with Ki67 LI, Bax, Grp78, and TS expression. On multiple logistic regression analysis, Ki67 LI, Bax, and TS scores were found to be independent factors. With their use in a logistic model, P-values could predict responder cases with a sensitivity of 82.8% and a specificity of 83.9%.

Conclusion

Using this system, treatment strategy for locally advanced rectal cancers can be determined before chemoradiation.

Preoperative serum vascular endothelial growth factor-a is a marker for subsequent recurrence in colorectal cancer patients

PURPOSE

Serum vascular endothelial growth factor-A has been associated with stage of disease and prognosis in colorectal cancer. In this study, the clinical usefulness of preoperative serum vascular endothelial growth factor-A concentrations in the long-term follow-up of colorectal cancer patients was evaluated.

METHODS

Serum vascular endothelial growth factor-A levels were determined by quantitative enzyme-linked immunosorbent assay in 93 patients prior to resection for colorectal cancer: node-negative (n = 41) and node-positive (n = 52). Median follow-up for patients without cancer death was 54 (interquartile range, 24-63.5) months.

RESULTS

The median preoperative serum vascular endothelial growth factor-A level of these patients was 168 (interquartile range, 48-414) pg/ml. Seven patients had local recurrences with a median time of 6 (interquartile range, 4-12) months. Patients (n = 17) that developed metastasis had a median time of 17 (interquartile range, 7-42) months. Patients with local recurrence had significantly higher levels of serum vascular endothelial growth factor-A (P = 0.01). By classifying the patients into two groups, using the maximal chi-squared value of the Cox's regression based on our previous work, it was found that a serum vascular endothelial growth factor-A level >575 pg/ml is an independent prognostic factor for predicting tumor recurrence.

CONCLUSION

Patients with colorectal cancer who have preoperative serum vascular endothelial growth factor-A levels >575 pg/ml are more likely to develop recurrence. Trials are warranted to investigate the efficacy of adjuvant therapy for this high-risk group.

Serum vascular endothelial growth factor and angiogenesis are related to the prognosis of patients with gastrointestinal stromal tumors

AIM

To investigate if serum vascular endothelial growth factor (SVEGF), tissue VEGF and microvessel density (MVD) have any relation to progress and prognosis in gastrointestinal stromal tumors (GIST).

METHODS

SVEGF was examined using ELISA. VEGF and MVD were examined using immunohistochemical staining.

RESULTS

The median level of SVEGF was higher in GIST than in controls. A higher level of SVEGF and a positive expression rate of VEGF were obtained in diameter >or=5 cm, mitotic count >or=2/10 high power fields (HPF), recurrence and high risk groups. The MVD of experimental was higher than that of controls. A higher MVD was observed in mitotic count >or=2/10HPF and recurrence groups. The median level of SVEGF was higher in the VEGF positive group than in the controls. The SVEGF presented a relationship with MVD. Factors predicating poor prognosis were SVEGF and VEGF.

CONCLUSIONS

SVEGF and VEGF show a correlation with poor prognosis of GIST.

Microvessel density as new prognostic marker after radiotherapy in rectal cancer

Background

The extent of angiogenesis is an important prognostic factor for colorectal carcinoma, however, there are few studies concerning changes in angiogenesis with radiotherapy (RTX). Our aim was to investigate changes in tumor angiogenesis influenced by radiotherapy to assess the prognostic value of angiogenesis the microvessel density (MVD) in overall survival after radiotherapy.

Methods

Tumor specimens were taken from 101 patients resected for rectal cancer. The patients were divided into three groups according to the treatment they received before surgery (not treated, a short course, or long course of RTX). Tumor specimens were paraffin-embedded and immunohistochemistry was performed with primary antibody against CD-34 to count MVD.

Results

MVD was significantly lower in the group of patients treated with a long course of RTX (p <0.025). The mean MVD for the long RTX group was 134.8; for the short RTX group – 192.5; and for those not treated with RTX – 193.0. There were no significant statistical correlations between MVD and age, sex, grade of tumor differentiation (G) and tumor size (T) in those untreated with RTX. In long RTX group we found a significant prognostic rate for MVD when the density cut off was near 130 with 92.3% sensitivity and 64.7% specificity. When the MVD was lower than a cut off of 130, the survival period significantly increased (p = 0.001), the mortality rate is significantly higher if the MVD is higher than 130 (microvessel/mm²) (1953.047; p = 0.002), if the histological grade is moderate/poor (127.407; p = 0.013), if the tumor is T3/T4 (111.618; p = 0.014), and if the patient is male (17.92; p = 0.034) adjusted by other variable in model.

Conclusion

Our results show that a long course of radiotherapy significantly decreased angiogenesis in rectal cancer tissue. MVD was found to be a favourable marker for tumor behaviour during RTX and a predictor of overall survival after long course of RTX. Further investigations are now needed to determine the changes in angiogenesis during a shorter course of RTX.

Clinical and biological significance of angiogenesis and lymphangiogenesis in colorectal cancer

BACKGROUND

Angiogenesis and lymphangiogenesis are essential for tumour development and progression. However, in colorectal cancer (CRC), the relationship between angiogenesis and clinical outcome is controversial, and the prognostic significance of lymphangiogenesis is not well examined because of the lack of specific a marker for lymphatic vessels.

AIMS

To evaluate blood microvessel density (MVD) following the proposed standard method for MVD assessment given by the first international consensus and lymphatic vessel density (LVD), and investigate their clinicopathologic and biologic significance in CRC.

METHODS

MVD and LVD in primary tumours (n=210), along with their corresponding adjacent normal mucosa (n=105) and distant normal mucosa (n=27) specimens, were immunohistochemically examined by using CD31 and D2-40 antibodies.

RESULTS

Both MVD and LVD were higher in tumour compared with the corresponding normal mucosa. In tumours, MVD was positively related to particular interesting new cysteine-histidine-rich protein (PINCH) expression (P=0.006), but not with clinicopathologic variables. LVD, in both intratumoural and peritumoural areas of tumours, was reversely related to Dukes' stage. There was no association between MVD or LVD and patients' survival (P>0.05).

CONCLUSIONS

Angiogenesis and lymphangiogenesis occurred in CRC development, but were not related to CRC patient prognosis. PINCH may play a potential role in tumour angiogenesis.

VEGF gene polymorphisms and susceptibility to colorectal cancer disease in Italian population

BACKGROUND

The vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen involved in the process of angiogenesis, a crucial phase in tumor growth and metastasis. We carried out a case-control study to evaluate whether polymorphisms of VEGF gene modulate the risk of developing colorectal cancer disease (CCD).

MATERIALS AND METHODS

We evaluated VEGF -2578A/C, -460T/C, and +405C/G genotypes obtained from a series of 302 CCD patients and 115 controls from the Italian population using polymerase chain reaction restriction fragment length polymorphism assay.

RESULTS

Strong linkage disequilibrium (LD) was detected between -2578A/C and -460T/C (D' = 0.97; CI = 0.93-1) and between -2578A/C and +405C/G (D' = 0.97; CI = 0.98-1) in the case group. Complete LD was detected between -2578A/C and +405C/G and between -460T/C and +405C/G (D' = 1; CI = 0.84-1; CI = 0.82-1, respectively) in the control group. A reduced risk for the disease was associated with -2578C/A and -2578C/C (odds ratio (OR) = 0.34, CI = 0.162-0.676 and OR = 0.38, CI = 0.181-0.775, respectively). A direct association was found for carriers of the VEGF -460C/C polymorphism (OR = 3.55; CI = 1.659-8.469). We identified a protective haplotype -2578A, -460T, and +405G (OR = 0.04; CI = 0.009-0.19) and two different high-risk haplotypes -2578A, -460C, and +405G (OR = 1.90; CI = 1.31-2.27) and -2578C, -460C, and +405C (OR = 9.62; CI = 1.3-70.87).

CONCLUSIONS

The present study suggests that the VEGF gene polymorphisms may play a role in the development of colorectal cancer.

Colorectal tumor vascularity: quantitative assessment with multidetector CT--do tumor perfusion measurements reflect angiogenesis?

PURPOSE

To establish the relationships between quantitative perfusion computed tomography (CT) parameters-specifically, primary tumor blood flow, blood volume, transit time, and permeability surface-area product-and immunohistologic markers of angiogenesis in colorectal cancer.

MATERIALS AND METHODS

After institutional review board approval and informed patient consent were obtained for this prospective study, 23 patients (11 men, 12 women; mean age, 68.4 years; age range, 34.8-87.1 years) with colorectal adenocarcinoma underwent a 65-second perfusion CT examination, and tumor blood flow, blood volume, mean transit time, and permeability surface-area product were determined. After surgery, resected specimens were sectioned and stained immunohistochemically to identify CD34 for quantification of microvessel density (MVD), to identify smooth muscle actin for assessment of pericyte coverage index, to identify vascular endothelial growth factor (VEGF), and to identify glucose transporter protein (GLUT-1). Perfusion CT measurements were correlated with MVD, pericyte coverage index, VEGF expression, and GLUT-1 expression by using Pearson or Spearman rank correlation analysis, with significance assigned at the 5% level.

RESULTS

Mean blood flow, blood volume, transit time, and permeability surface-area product values were 72.1 mL/min/100 g of tissue +/- 28.4 (standard deviation), 6.2 mL/100 g of tissue +/- 1.4, 9.3 seconds +/- 3.9, and 13.9 mL/min/100 g of tissue +/- 3.2, respectively. Blood volume (r = 0.59, P = .002) and permeability surface-area product (r = 0.46, P = .03) correlated positively with MVD, but blood flow (r = 0.27, P = .22) and transit time (r = -0.18, P = .44) did not. There were no significant associations between any perfusion CT parameter and pericyte coverage index (r <or= 0.36, P > .05), VEGF score (rho <or= 0.30, P >or= .15), or GLUT-1 score (rho < 0.21, P >or= .33).

CONCLUSION

Tumor permeability surface-area product and blood volume correlate positively with MVD and may reflect the microvascularity of colorectal tumors.

Can perfusion CT assessment of primary colorectal adenocarcinoma blood flow at staging predict for subsequent metastatic disease? A pilot study

We aimed to determine whether perfusion CT measurements at colorectal cancer staging may predict for subsequent metastatic relapse. Fifty two prospective patients underwent perfusion CT at staging to estimate tumour blood flow, blood volume, mean transit time, and permeability surface area product. Patients considered metastasis free and suitable for surgery underwent curative resection subsequently. At final analysis, a median of 48.6 months post-surgery, patients were divided into those who remained disease free, and those with subsequent metastases. Vascular parameters for these two groups were compared using t-testing, and receiver operator curve analysis was performed to determine the sensitivity and specificity of these vascular parameters for predicting metastases. Thirty seven (71%) patients underwent curative surgery; data were available for 35: 26 (74%) remained disease free; 9 (26%) recurred (8 metastatic, 1 local). Tumour blood flow differed significantly between disease-free and metastatic patients (76.0 versus 45.7 ml/min/100 g tissue; p = 0.008). With blood flow <64 ml/min/100 g tissue, sensitivity and specificity (95% CI) for development of metastases were 100% (60-100%) and 73% (53-87%), respectively. Our preliminary findings suggest that primary tumour blood flow might potentially be a useful predictor warranting further study.

Expression of vascular endothelial growth factor expression and its relation with growth, invasion and metastasis of human colorectal cancer

AIM: To explore the relations of vascular endothelial growth factor (VEGF) expression with the growth, invasion and metastasis of colorectal cancer.

METHODS: We collected 23 fresh colorectal cancerous, distal cancerous tissues resected during operation, 16 colon polyps and 45 serum samples from colon cancer patients. The expression of VEGF in colorectal tissues and serum samples was detected by nested reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The relationship was also analyzed between VEGF expression and Duke's staging.

RESULTS: The expression of VEGF mRNA was significantly higher in the colorectal cancer tissues than that in the distal cancerous tissues or colon polyps (65.22% vs 21.74%, 18.75%, both P < 0.01). VEGF mRNA expression was positive in 3 patients (37.5%) with Duke's stage A or B, and it was positive in 12 patients with (80.0%) stage C or D; there was significant difference between them (P < 0.05). The level of serum VEGF was markedly higher in patients with stage C or D than that in patients with stage A or B (716.71 + 229.39 ng/L vs 312.30 + 103.61 ng/L, P < 0. 01).

CONCLUSION: VEGF can serve as an index in predicting the growth, invasion and metastasis of colorectal cancer.

Sialyl Lewis X expression and lymphatic microvessel density in primary tumors of node-negative colorectal cancer patients predict disease recurrence

Up to 30% of curatively resected colorectal cancer patients with tumor-negative lymph nodes, show disease recurrence. We assessed whether these high-risk patients can be identified by examining primary tumors for the following blood and lymphatic vasculature markers: A) sialyl Lewis X (sLeX), vascular endothelial growth factor (VEGF)-C and VEGF-D expression; B) blood and lymphatic microvessel density (BMVD/LMVD); and C) the presence of blood and lymphatic vessel invasion. Thirty-six cases (disease recurrence within 5 years) and 72 controls (no disease recurrence for at least 5 years) were selected in a case-control design. Tumor sections were stained by antibodies CSLEX1 (sLeX), anti-VEGF-C, anti-VEGF-D, anti-CD31 (BMVD) or D2–40 (LMVD) to determine the parameters as mentioned above. A multivariate analysis showed sLeX expression and high LMVD (odds ratio 5.1, 95% confidence interval 1.3–20.0 and odds ratio 3.1, 95% confidence interval 1.0–10.0, respectively) to be independent factors predicting disease recurrence. Expression of sLeX correlated with liver metastases (P = 0.015). A high LMVD was related to regional intra-abdominal or intrapelvic metastases in lymph nodes and distant metastases other than in the liver and lungs such as peritoneum, bones, brain and adrenal glands (P = 0.004). A high BMVD in the invasive front correlated with lung metastases (P = 0.018). We show that high-risk node-negative colorectal cancer patients can be identified by primary tumor assessment for sLeX expression and LMVD. Our results are consistent with the notion that both lymphatic and hematogenous metastasis play a role in colorectal cancer.

Relationship between human tumour angiogenic profile and combretastatin-induced vascular shutdown: an exploratory study

Combretastatin-A4-phosphate (CA4P) acts most effectively against immature tumour vasculature. We investigated whether histological angiogenic profile can explain the differential sensitivity of human tumours to CA4P, by correlating the kinetic changes demonstrated by dynamic MRI (DCE-MRI) in response to CA4P, with tumour immunohistochemical angiogenic markers. Tissue was received from 24 patients (mean age 59, range 32-73, 18 women, 6 men). An angiogenic profile was performed using standard immunohistochemical techniques. Dynamic MRI data were obtained for the same patients before and 4 h after CA4P. Three patients showed a statistically significant fall in K(trans) following CA4P, and one a statistically significant fall in IAUGC(60). No statistically significant correlations were seen between the continuous or categorical variables and the DCE-MRI kinetic parameters other than between ang-2 and K(trans) (P=0.044). In conclusion, we found no strong relationships between changes in DCE-MRI kinetic variables following CA4P and the immunohistochemical angiogenic profile.

In vivo optical molecular imaging of vascular endothelial growth factor for monitoring cancer treatment

PURPOSE

Vascular endothelial growth factor (VEGF) expression is a critical component in tumor growth and metastasis. Capabilities to monitor VEGF expression in vivo can potentially serve as a useful tool for diagnosis, prognosis, treatment planning, monitoring, and research. Here, we present the first report of in vivo hyperspectral molecular imaging strategy capable of monitoring treatment-induced changes in VEGF expression.

EXPERIMENTAL DESIGN

VEGF was targeted with an anti-VEGF antibody conjugated with a fluorescent dye and was imaged in vivo using a hyperspectral imaging system. The strategy was validated by quantitatively monitoring VEGF levels in three different tumors as well as following photodynamic treatment. Specificity of the molecular imaging strategy was tested using in vivo competition experiments and mathematically using a quantitative pharmacokinetic model.

RESULTS

The molecular imaging strategy successfully imaged VEGF levels quantitatively in three different tumors and showed concordance with results from standard ELISA. Changes in tumoral VEGF concentration following photodynamic treatment and Avastin treatment were shown. Immunohistochemistry shows that (a) the VEGF-specific contrast agent labels both proteoglycan-bound and unbound VEGF in the extracellular space and (b) the bound VEGF is released from the extracellular matrix in response to photodynamic therapy. In vivo competition experiments and quantitative pharmacokinetic model-based analysis confirmed the high specificity of the imaging strategy.

CONCLUSION

This first report of in vivo quantitative optical molecular imaging-based monitoring of a secreted cytokine in tumors may have implications in providing tools for mechanistic investigations as well as for improved treatment design and merits further investigation.

Vascular endothelial growth factor gene polymorphisms associated with prognosis for patients with colorectal cancer

PURPOSE

Vascular endothelial growth factor (VEGF) or its family may be considered to play an important role in lymphangiogenesis and lymphatic tumor spread, thereby affecting prognosis of colorectal cancer. Accordingly, the present study analyzed VEGF gene polymorphisms and their effect on the prognosis for patients with colorectal cancer.

EXPERIMENTAL DESIGN

Four hundred and forty-five consecutive patients with surgically treated colorectal adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from fresh colorectal tissue and three VEGF (-2578C>A, -634G>C, and +936C>T) gene polymorphisms were determined using a PCR/denaturing high-performance liquid chromatography assay.

RESULTS

Multivariate survival analysis showed that the survival for the patients with the -634 G/C genotype [overall survival (OS): hazard ratio (HR), 0.158; P < 0.001] or C/C genotype (OS: HR, 0.188; P < 0.001) were better than for the patients with the -634G/G genotype, whereas the +936 C/T genotype (OS: HR, 12.809; P < 0.001) or T/T genotype (OS: HR, 37.260; P < 0.001) was associated with a worse survival compared with the +936 C/C genotype. In haplotype analysis, the -2578A/-634G/+936T haplotype exhibited a significantly worse survival when compared with the wild -2578C/-634G/+936C haplotype (OS: HR, 3.866; P < 0.001).

CONCLUSIONS

VEGF gene polymorphisms were found to be an independent prognostic marker for patients with colorectal cancer. Accordingly, the analysis of VEGF gene polymorphisms can help identify patient subgroups at high risk of a poor disease outcome.

Antiangiogenic therapy and surgical practice

Background

Antiangiogenic therapy has become a reality with the recent introduction of bevacizumab, a monoclonal antibody against vascular endothelial growth factor.

Methods

Relevant medical literature from PubMed, National Institute for Health and Clinical Excellence and National Institutes of Health websites to August 2007 was reviewed.

Results and conclusions

Although often described as the fourth modality of treatment after surgery, radiotherapy and chemotherapy, many antiangiogenic drugs have failed to live up to expectations. Nevertheless, research continues and there are reasons to believe that antiangiogenic therapy may yet have a future in the clinical setting.

Investigation of two dosing schedules of vandetanib (ZD6474), an inhibitor of vascular endothelial growth factor receptor and epidermal growth factor receptor signaling, in combination with irinotecan in a human colon cancer xenograft model

PURPOSE

This in vivo study was designed to determine the optimal doses and schedules of vandetanib, a dual epidermal growth factor receptor (EGFR)-vascular endothelial growth factor receptor tyrosine kinase inhibitor, in combination with irinotecan in a murine xenograft model of human colon cancer.

EXPERIMENTAL DESIGN

HT-29 tumor-bearing nude mice were treated with two doses of vandetanib (12.5 and 25 mg/kg/d) with or without irinotecan (100 mg/kg) using either sequential or concurrent schedules for 30 days. Tumor size was measured using standard variables, whereas the antiangiogenic response was evaluated using dynamic contrast-enhanced magnetic resonance imaging. Additionally, effects on EGFR-dependent signal transduction pathways and proliferation were assessed using immunohistochemistry. These pharmacodynamic end points were then evaluated for associations with antitumor efficacy and/or to plasma/tumor concentrations of vandetanib.

RESULTS

The greatest antitumor efficacy was observed in the groups receiving the highest dose of vandetanib given continuously (concurrent schedule), alone or in combination with irinotecan. These dosing schedules resulted in significant effects on tumor vasculature, with decreased volume transfer constants, area under the curve, and permeability surface factor as well as increased gadolinium clearance after 30 days of treatment. In addition, these groups showed the greatest inhibition of EGFR signaling. Interestingly, tumor concentrations of vandetanib were increased by irinotecan in the concurrent schedule, possibly due to decreased tumor perfusion in this group.

CONCLUSIONS

These data suggest that higher, sustained concentrations of vandetanib (versus intermittent), alone and in combination with irinotecan, result in optimal antitumor efficacy in this model and may have implications for the design of future clinical studies with this drug.

VEGF signaling inhibitors: more pro-apoptotic than anti-angiogenic

The vascular endothelial growth factor (VEGF) family of polypeptide growth factors regulates a family of VEGF receptor (VEGFR) tyrosine kinases with pleiotropic downstream effects. Angiogenesis is the best known of these effects, but additional VEGF-dependent actions include increased vascular permeability, paracrine/autocrine growth factor release, enhancement of cell motility, and inhibition of apoptosis. In theory, therapeutic inhibition of angiogenesis should reduce tumor perfusion and thus increase tumor hypoxia and chemoresistance, but in clinical practice the VEGF antibody bevacizumab acts as a broad-spectrum chemosensitizer. Since VEGFR expression occurs in many tumor types, such chemosensitization is more readily explained by direct inhibition of tumor cell survival signals than by indirect stromal/vascular effects. The emerging model of anti-VEGF drug action being mediated primarily by tumoral (as distinct from endothelial) VEGFRs has clinically important implications for optimizing the anti-metastatic efficacy of this expanding drug class.

Node-Negative Colorectal Cancer at High Risk of Distant Metastasis Identified by Combined Analysis of Lymph Node Status, Vascular Invasion, and Raf-1 Kinase Inhibitor Protein Expression

Purpose: To identify independent clinicopathologic factors and protein markers leading to the identification of colorectal cancer (CRC) patients with mismatch repair proficiency at risk of developing metastasis and, consequently, more likely to benefit from combined modality therapy.

Experimental Design: Immunohistochemistry for 22 tumor markers was done using a tissue microarray. A subset of 387 CRC patients with complete clinicopathologic data and TNM stage was analyzed. Univariate and multivariate analyses were done to identify independent predictive markers of metastasis. The results were validated on 810 CRC patients.

Results: In univariate analysis, T stage (P &lt; 0.001), N stage (P &lt; 0.001), tumor grade (P = 0.005), vascular invasion (P &lt; 0.001), tumor budding (P &lt; 0.001), positive expression of β-catenin (P = 0.015), overexpression of RHAMM (P = 0.008), negative expression of Raf-1 kinase inhibitor protein (RKIP; P = 0.001), and absence of intraepithelial lymphocytes (P = 0.017) were significantly associated with the presence of distant metastasis. In multivariate analysis, higher N stage (P &lt; 0.001), presence of vascular invasion (P = 0.009), and RKIP loss (P = 0.003) independently predicted distant metastatic disease. A subgroup of node-negative patients was identified as high risk for distant metastasis and showed a similar probability of metastatic risk and nearly identical survival times as node-positive patients with absence of vascular invasion and positive RKIP expression (metastatic risk, 24% and 22%; median survival time, 45.0 and 47.0 months, respectively).

Conclusion: The combined analysis of N stage, vascular invasion, and RKIP expression is highly predictive of distant metastasis in patients with mismatch repair–proficient CRC. Additionally, a subgroup of more aggressive N0 tumors can be identified by evaluating vascular invasion and RKIP expression.

Peritumoural, but not intratumoural, lymphatic vessel density and invasion correlate with colorectal carcinoma poor-outcome markers

To evaluate whether lymphatic vessel density (LVD) and lymphatic vessel invasion (LVI) are useful markers of worse outcome in colorectal carcinoma and if LVD and LVI correlate to the classical clinical-pathological parameters, we analysed 120 cases of colorectal carcinomas selected from the files of Division of Pathology, Hospital das Clinicas, São Paulo University, Brazil. Assessment of LVD and LVI was performed by immunohistochemical detection of lymphatic vessels, using the monoclonal antibody D2-40. Higher LVD was found in the intratumoural area, when comparing with normal and peritumoural areas (p < 0.001). However, peritumoural LVD, but not intratumoural, correlated with both colonic-wall-invasion depth (p = 0.037) and liver metastasis (p = 0.012). Remarkably, LVI was found associated with local invasion (p = 0.016), nodal metastasis (p = 0.022) and hepatic metastasis (p < 0.001). Peritumoural LVD and LVI are directly related to histopathological variables indicative of poor outcome such as lymph-node status and liver metastasis.

Clinicopathological and prognostic significance of EGFR, VEGF, and HER2 expression in cholangiocarcinoma

Epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and human epidermal growth factor receptor 2 (HER2) have been considered as potential therapeutic targets in cholangiocarcinoma, but no studies have yet clarified the clinicopathological or prognostic significance of these molecules. Immunohistochemical expression of these molecules was assessed retrospectively in 236 cases of cholangiocarcinoma, as well as associations between the expression of these molecules and clinicopathological factors or clinical outcome. The proportions of positive cases for EGFR, VEGF, and HER2 overexpression were 27.4, 53.8, and 0.9% in intrahepatic cholangiocarcinoma (IHCC), and 19.2, 59.2, and 8.5% in extrahepatic cholangiocarcinoma (EHCC), respectively. Clinicopathologically, EGFR overexpression was associated with macroscopic type (P=0.0120), lymph node metastasis (P=0.0006), tumour stage (P=0.0424), lymphatic vessel invasion (P=0.0371), and perineural invasion (P=0.0459) in EHCC, and VEGF overexpression with intrahepatic metastasis (P=0.0224) in IHCC. Multivariate analysis showed that EGFR expression was a significant prognostic factor (hazard ratio (HR), 2.67; 95% confidence interval (CI), 1.52-4.69; P=0.0006) and also a risk factor for tumour recurrence (HR, 1.89; 95% CI, 1.05-3.39, P=0.0335) in IHCC. These results suggest that EGFR expression is associated with tumour progression and VEGF expression may be involved in haematogenic metastasis in cholangiocarcinoma.

A fibrotic focus is a prognostic factor and a surrogate marker for hypoxia and (lymph)angiogenesis in breast cancer: review of the literature and proposal on the criteria of evaluation

A fibrotic focus is a scar-like area in the centre of a carcinoma and can be regarded as a focus of exaggerated reactive tumour stroma formation. Although modern surgical pathology uses different histopathological and molecular markers to assess the aggressiveness and predict the behaviour of malignant tumours, markers reflecting stromal cell behaviour and interactions between epithelial cells and stromal cells are scarce. In this review we summarize all studies investigating the value of a fibrotic focus as a prognostic factor and as a surrogate marker for hypoxia and (lymph)angiogenesis in patients with breast cancer. These data show that a fibrotic focus can be used as a practical, easily assessable and reproducible integrative histological prognostic parameter in breast cancer. We propose a consensus methodology to assess the fibrotic focus in breast cancer.

The angiogenic switch occurs at the adenoma stage of the adenoma carcinoma sequence in colorectal cancer

OBJECTIVE

The aim of this study was to examine the relationship between tissue factor (TF), vascular endothelial growth factor (VEGF) and the onset of angiogenesis in the adenoma-carcinoma sequence (ACS), the stepwise process encompassing colorectal cancer (CRC) disease progression.

PATIENTS AND METHODS

210 surgical specimens comprising the ACS were immunohistochemically stained for endothelial cells (CD31), VEGF and TF. Angiogenesis quantified using Chalkley grid analysis (microvascular density; MVD), and VEGF/TF expression were semiquantitatively graded and correlated with standard prognostic indicators including 5 year follow-up. VEGF and TF were measured by ELISA in tumour specimens and normal mucosa from an additional 90 CRC patients.

RESULTS

There was a significant increase in MVD across the ACS (p < 0.0005) with significant correlations with Dukes' stage (p = 0.01) and lymph node involvement (p = 0.02). The greatest increase in MVD was related to the onset of dysplasia, with an associated significant increase in VEGF expression (p < 0.0005). There was a significant relationship between VEGF and TF expression in the initial phase of the ACS (k = 0.44, p < 0.005), although no correlation between VEGF or TF, and MVD, tumour size, Dukes' classification, lymph node involvement or survival was found.

CONCLUSIONS

These findings are the first to suggest that the angiogenic switch occurs at the onset of dysplasia in the ACS, and provide further evidence of the close association between VEGF and TF in the early stages of CRC development.

Antiangiogenic therapy for normalization of atherosclerotic plaque vasculature: a potential strategy for plaque stabilization

Angiogenesis within human atherosclerotic plaques has an important role in plaque progression as immature blood vessels leak red blood cells and inflammatory mediators into the plaque center. Accumulation of free cholesterol from red blood cell membranes potentially increases the size of the necrotic core and triggers a chain of events that promote plaque destabilization. Antiangiogenic agents have been shown to prune some tumor vessels and 'normalize' the structure and function of the remaining vasculature, thereby improving the access of chemotherapeutic agents to tumors. We propose that antiangiogenic therapy can similarly stabilize vulnerable 'rupture-prone' plaques by pruning and normalizing immature intraplaque vessels, preventing further intraplaque hemorrhage. This normalization would limit necrotic core enlargement, further luminal narrowing and the degree of inflammation. Such normalization has been realized using vascular endothelial growth factor antagonists for the treatment of cancer and age-related macular degeneration. The development of this novel approach to prevent plaque progression might add to the armamentarium of preventive measures for acute myocardial infarction, stroke and sudden cardiac death.

Prognostic significance of VEGF expression evaluated by quantitative immunohistochemical analysis in colorectal cancer

BACKGROUND

The prognostic value of vascular endothelial growth factor (VEGF) expression in colorectal cancer is still unclear, as shown by the discordant results still reported in the literature. The aim of the study was to examine the expression of VEGF in colorectal adenocarcinomas and investigate its prognostic relevance.

MATERIALS AND METHODS

VEGF expression was investigated by immunohistochemistry performed on tissue microarrays, in a series of 117 colorectal cancer specimens. The VEGF staining intensity in the cytoplasm of tumor cells was quantified using a semi-automated computerized image analysis and correlated with various clinicopathological characteristics and survival.

RESULTS

All tumors evaluated showed expression of VEGF, which were further divided into 49 high expression and 68 low expression tumors by their staining intensity. In tumors with lymph node metastasis, the intensity of staining of VEGF was more intense than in those without (P < 0.0001). Furthermore, the intensity of VEGF staining was more intense in Stage III tumors than those in Stage I/II (P < 0.0001). The mean number of involved lymph nodes in tumors with high VEGF staining intensity was significantly greater than in those with low staining intensity (P = 0.031). Survival analysis showed a significant correlation between high levels of VEGF staining intensity and poor disease-specific survival (P < 0.0001), with independent prognostic significance in multivariate analysis (RR = 3.5, P < 0.0001). In addition, patients with Stage II disease and high staining intensity of VEGF had a significantly worse disease-specific survival than those with low staining intensity (P = 0.001).

CONCLUSIONS

VEGF expression in colorectal cancer seems to be an independent prognostic marker of tumor behavior and may be useful to identify patients with unfavorable clinical outcome.

Prognostic value of carcinoembryonic antigen and vascular endothelial growth factor tumor tissue content in colorectal cancer

AIM

This study was designed to assess the prognostic significance of the combined measurement of vascular endothelial growth factor (VEGF) and carcinoembryonic antigen (CEA) tissue content with respect to relapse-free and overall survival of patients with colorectal cancer (CRC).

METHODS

Quantitative evaluation of VEGF and CEA content was performed on protein extracts obtained from tissue biopsies from 69 CRC patients and 15 healthy donors.

RESULTS

VEGF significantly correlated with CEA content of either tumor tissues (rho = 0.55, p < 0.0001) or corresponding normal mucosa (rho = 0.34, p < 0.005). General regression analyses demonstrated that CEA was an independent predictor of VEGF tissue content either in CRC biopsies (regression coefficient = 0.57, p < 0.0001) or normal mucosa (regression coefficient = 0.25, p < 0.05). Cox proportional hazards survival analysis showed that tumor tissue content of both VEGF and CEA had an independent prognostic value in predicting both relapse-free (hazards ratio = 5.98, p = 0.002) and overall (hazards ratio = 4.73, p = 0.007) survival, irrespective of Dukes' stage. Kaplan-Meier analysis demonstrated that an elevated tumor content of both CEA and VEGF had a negative prognostic value in respect to either relapse-free (log-rank test: 10.4, p = 0.001) or overall survival (log-rank test: 7.33, p = 0.007).

CONCLUSION

Tumor tissue VEGF and CEA content determination might add useful prognostic information in the management of patients with CRC.

Angiogenesis: an organizing principle for drug discovery?

Angiogenesis--the process of new blood-vessel growth--has an essential role in development, reproduction and repair. However, pathological angiogenesis occurs not only in tumour formation, but also in a range of non-neoplastic diseases that could be classed together as 'angiogenesis-dependent diseases'. By viewing the process of angiogenesis as an 'organizing principle' in biology, intriguing insights into the molecular mechanisms of seemingly unrelated phenomena might be gained. This has important consequences for the clinical use of angiogenesis inhibitors and for drug discovery, not only for optimizing the treatment of cancer, but possibly also for developing therapeutic approaches for various diseases that are otherwise unrelated to each other.

Prognostic value of serum angiogenic activity in colorectal cancer patients

Angiogenesis, resulting from an imbalance between angiogenic activator factors and inhibitors, is required for tumour growth and metastasis. The determination of the circulating concentration of all angiogenic factors (activators and inhibitors) is not feasible at present. We have evaluated diagnostic and prognostic values of the measurement of serum angiogenic activity in colorectal carcinoma (CRC) patients. Serum proliferative activity (PA) on human umbilical vein endothelial cells (HUVEC) in vitro, and serum vascular endothelial growth factor (VEGF) levels were determined by ELISA in 53 patients with primary CRC, 16 subjects with non-neoplastic gastrointestinal disease (SC) and 34 healthy individuals. Data were compared with clinical outcome of the patients. Although serum from CRC patients significantly increased the PA of HUVEC, compared to culture control (HUVEC in medium + 10% foetal bovine serum (FBS); P < 0.001); our results indicate that serum PA in CRC patients was similar to that of SC or healthy individuals. There was no correlation between serum PA and circulating VEGF concentrations. Surgery produced a decrease of PA at 8 hrs after tumour resection in CRC patients compared to pre-surgery values (186 +/- 47 versus 213 +/- 41, P < 0.001). However, an increase in serum VEGF values was observed after surgery (280 [176-450] versus 251 [160-357] pg/ml, P = 0.004). Patients with lower PA values after surgery showed a worse outcome that those with higher PA values. Therefore, this study does not support a diagnostic value for serum angiogenic activity measured by proliferative activity on HUVEC but suggests it could have a prognostic value in CRC patients.

Functional imaging of colorectal cancer angiogenesis

Angiogenesis is a key factor in the growth and dissemination of colorectal cancer, with significant implications for its clinical management. Previous trials have provided proof-of-principle that inhibition of angiogenesis has the potential to enhance the effectiveness of treatment for this disease. Characterisation of the angiogenic status of the tumour on an individual patient basis could allow for a more targeted approach to treatment. In vivo imaging techniques that assess tumour microvessel function have the potential to improve the management of treatment for patients with colorectal cancer. This review focuses on MRI and CT assessment of colorectal cancer angiogenesis. We discuss the effects that these two techniques have had in the assessment of this disease, including tumour staging and therapeutic assessment. Their comparability with other imaging techniques, in particular ultrasound, and their limitations are also addressed.

Prognostic significance of vascular endothelial cell growth factors -A, -C and -D in breast cancer and their relationship with angio- and lymphangiogenesis

Vascular endothelial cell growth factors (VEGF)-A, -C and -D have potent angio and lymphangiogenic functions in experimental models, although their role in the progression of human breast cancer is unclear. The aims of the current study were to examine the relationship between the expression of the aforementioned growth factors with the angio and lymphangiogenic characteristics of breast cancer, and to assess their suitability as potential prognostic factors. Paraffin-embedded sections of 177 primary invasive breast cancer, with complete clinical follow-up information for 10 years, were stained for VEGF-A, -C, -D, podoplanin and CD34 using standard immunohistochemical approaches. The expression of the growth factors was correlated with clinicopathological criteria and patients’ survival. Lymph vessel density (LVD) and microvessel density (MVD) were assessed and correlated with expression of the growth factors. Vascular endothelial cell growth factor-A, -C and -D were highly expressed in 40, 37 and 42% of specimens, respectively. High expression of VEGF-A and - C, but not of -D, was associated with a higher LVD (P=0.013 and P=0.014, respectively), a higher MVD (P<0.001 and P=0.002, respectively), the presence of lymph node metastasis (P<0.001 and P<0.001, respectively), distant metastasis (P=0.010 and P=0.008, respectively) and a shorter Overall Survival (P=0.029 and 0.028, respectively). In conclusion, breast cancers that express high levels of VEGF-A and -C are characterised by a poor prognosis, likely through the induction of angio and lymphangiogenesis. Examination of expression of VEGF-A and -C in breast cancer may be beneficial in the identification of a subset of tumours that have a higher probability of recurrence and metastatic spread.