Intratumoral microvessel density predicts local treatment failure of radically irradiated squamous cell cancer of the oropharynx

Expression, Prognostic Value and Correlation with HPV Status of Hypoxia-Induced Markers in Sinonasal Squamous Cell Carcinoma

(1) Background: In head and neck squamous cell carcinoma, tumor hypoxia has been associated with radio/chemoresistance and poor prognosis, whereas human papillomavirus (HPV)-positive status has a positive impact on treatment response and survival outcomes. The aim of this study was to evaluate the expression and the potential prognostic value of hypoxia-induced endogenous markers in patients treated for squamous cell carcinoma of the nasal cavity and paranasal sinuses (SNSCC), and their correlation with HPV status. (2) Methods: In this monocentric study, patients treated in a curative intent for a SNSCC were screened retrospectively. Protein expression of CA-IX, GLUT-1, VEGF, VEGF-R1, and HIF-1α was determined by immunohistochemical staining, scored, and then correlated with overall survival (OS) and locoregional recurrence free survival (LRRFS). HPV status was assessed and correlated with hypoxic markers. (3) Results: 40 patients were included. A strong expression of CA-IX, GLUT-1, VEGF, and VEGF-R1 was detected in 30%, 32.5%, 50%, and 37.5% of cases, respectively. HIF-1α was detected in 27.5% of cases. High CA-IX expression was associated in univariate analysis with poor OS (p = 0.035), but there was no significant association between GLUT-1, VEGF, VEGF-R1, and HIF-1α expression, and OS/LRRFS. There was no correlation found between HPV status and hypoxia-induced endogenous markers (all p > 0.05). (4) Conclusions: This study provides data on the expression of hypoxia-induced endogenous markers in patients treated for SNSCC and underlines the potential role of CA-IX as a prognostic biomarker for SNSCC.

Prognostic value of matrix metalloproteinases in oral squamous cell carcinoma

The aim of this study was to investigate whether there is a correlation between the expressions of four matrix metalloproteinases (MMPs): MMP-2, MMP-7, MMP-9 and MMP-13, and the TNM (tumour–node–metastasis) stages of oral squamous cell carcinoma (OSCC); and to explore the implication of these MMPs in OSCC dissemination. Samples from 61 patients diagnosed with oropharyngeal tumour were studied by immunohistochemistry against MMP-2, MMP-7, MMP-9 and MMP-13. The assessment of immunoreactivity was semi-quantitative. The results showed that MMP-2 and MMP-9 had similar expression patterns in the tumour cells with no changes in the immunoreactivity during tumour progression. MMP-9 always had the highest expression, whereas that of MMP-2 was moderate. MMP-7 showed a significant decrease in expression levels during tumour evolution. MMP-13 had constant expression levels within stage T2 and T3, but showed a remarkable decline in immunoreactivity in stage T4. No significant differences in the MMPs immunoreactivity between tumour cells and stroma were observed. Although strong evidence for the application of MMPs as reliable predictive markers for node metastasis was not acquired, we believe that combining patients’ MMPs expression intensity and clinical features may improve the diagnosis and prognosis. Strong evidence for the application of MMPs as reliable predictive markers for node metastasis was not acquired. Application of MMPs as prognostic indicators for the malignancy potential of OSCC might be considered in every case of tumour examination. We believe that combining patients’ MMPs expression intensity and clinical features may improve the process of making diagnosis and prognosis.

Prognostic biomarkers of survival in oropharyngeal squamous cell carcinoma: systematic review and meta-analysis

BACKGROUND

Human papillomavirus (HPV) positivity improves prognosis in patients with oropharyngeal squamous cell carcinoma (OPSCC). Combining HPV status with other biomarkers may improve its prognostic power.

METHODS

The approach was a literature search for longitudinal studies of biomarkers in OPSCC, with systematic review and meta-analysis.

RESULTS

In all, 3130 articles were identified; 32 satisfied the inclusion and exclusion criteria. On meta-analysis, there was a significant overall survival (OS) benefit for patients with HPV positive and p16 positive tumors. There was some evidence of improved OS of OPSCC patients with raised bcl2; amplification of 11q3 and loss of 16q genes; and low c-met, ki67, IMD, PLK, FHIT, nuclear surviving, or nuclear cyclin D1. However, none of these was suitable for meta-analysis.

CONCLUSION

Survival from OPSCC is associated with several biomarkers, which constitute potential targets for research into improving the prognostic power of HPV in OPSCC. Larger trials are needed, with standardization of cut-points and adherence to consensus reporting guidelines.

Prognostic value of vascular endothelial growth factor in patients with head and neck cancer: A meta-analysis

BACKGROUND

The correlation between vascular endothelial growth factor (VEGF) overexpression and the clinical outcome of head and neck cancer remains inconclusive. This meta-analysis aimed to evaluate the prognostic value of VEGF in patients with head and neck cancer.

METHODS

We searched Ovid MEDLINE, EMBASE and 2 Chinese science databases in order to enroll all eligible articles. Forty-seven studies were included in this meta-analysis. All results were evaluated by the random-effects model.

RESULTS

VEGF overexpression is significantly associated with worse overall survival (OS; hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.61-2.22) and progression-free survival (PFS; HR, 1.68; 95% CI, 1.33-2.12). Subgroup analysis reveals that VEGF overexpression is a significant poor predictor for nasopharyngeal cancer (HR, 1.66; 95% CI, 1.30-2.12) and salivary gland cancer (HR, 3.32; 95% CI, 1.61-6.84).

CONCLUSION

Our meta-analysis supports that VEGF overexpression is an available poor predictor for patients with head and neck cancer.

Monitoring PAI-1 and VEGF levels in 6 human squamous cell carcinoma xenografts during fractionated irradiation

PURPOSE

Previous studies have shown that the plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are regulated by hypoxia and irradiation and are involved in neoangiogenesis. The aim of this study was to determine in vivo whether changes in PAI-1 and VEGF during fractionated irradiation could predict for radiation resistance.

METHODS AND MATERIALS

Six xenografted tumor lines from human squamous cell carcinomas (HSCC) of the head and neck were irradiated with 0, 3, 5, 10, and 15 daily fractions of 2 Gy. The PAI-1 and VEGF antigen levels in tumor lysates were determined by enzyme-linked immunosorbent assay kits. The amounts of PAI-1 and VEGF were compared with the dose to cure 50% of tumors (TCD(50)). Colocalization of PAI-1, pimonidazole (hypoxia), CD31 (endothelium), and Hoechst 33342 (perfusion) was examined by immunofluorescence.

RESULTS

Human PAI-1 and VEGF (hVEGF) expression levels were induced by fractionated irradiation in UT-SCC-15, UT-SCC-14, and UT-SCC-5 tumors, and mouse VEGF (msVEGF) was induced only in UT-SCC-5 tumors. High hVEGF levels were significantly associated with radiation sensitivity after 5 fractions (P=.021), and high msVEGF levels were significantly associated with radiation resistance after 10 fractions (P=.007). PAI-1 staining was observed in the extracellular matrix, the cytoplasm of fibroblast-like stroma cells, and individual tumor cells at all doses of irradiation. Colocalization studies showed PAI-1 staining close to microvessels.

CONCLUSIONS

These results indicate that the concentration of tumor-specific and host-specific VEGF during fractionated irradiation could provide considerably divergent information for the outcome of radiation therapy.

Association of increased ligand cyclophilin A and receptor CD147 with hypoxia, angiogenesis, metastasis and prognosis of tongue squamous cell carcinoma

AIMS

We evaluated the association of ligand cyclophilin A (CypA) and receptor CD147 with hypoxia, angiogenesis, lymph node metastasis and prognosis of patients with tongue squamous cell carcinoma (TSCC).

METHODS AND RESULTS

We studied the expression of CypA, CD147, hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor A and C (VEGF-A and VEGF-C) protein by immunohistochemistry in 80 specimens of TSCC. CypA, CD147, HIF-1α, VEGF-A and VEGF-C were overexpressed in TSCCs, and were significantly higher than those in normal oral mucosa tissues (P<0.01). Increased ligand CypA and receptor CD147 correlated significantly with expression of HIF-1α, VEGF-A and VEGF-C. A significant relationship between VEGF-A and VEGF-C was also detected (P<0.01). Patients with overexpression of CypA, CD147, HIF-1α and VEGF-C had significantly worse overall survival (P<0.05) using Kaplan-Meier analysis. Multivariate Cox regression analysis showed that HIF-1α, recurrence and distant metastasis were independent prognostic factors on overall survival in TSCC patients.

CONCLUSIONS

The association of expression of ligand CypA and receptor CD147 with carcinogenesis, hypoxia, angiogenesis, metastasis and prognosis of TSCC suggests that ligand CypA and receptor CD147 may have prognostic value and could be regarded as potential therapeutic targets in TSCC.

Differential biomarker expression in head and neck cancer correlates with anatomical localization

We tested the expression of known (p16(ink4), Ki67, p53, EGFR) and a new immunohistochemical (collagen XVII/BP180) biomarker in head and neck squamous cell carcinomas (SCC) of diverse anatomical localization. Tissue microarrays (TMA) of 124 SCC were created, immunostained, and analyzed following whole slide digitalization using the Pannoramic Scan and the TMA Module software (3DHISTECH Kft, Budapest, Hungary). Statistical analysis of scoring results was carried out using Pearson's chi-square test. We observed the significant elevation of p16(ink4) and Ki67 expression in supraglottic, tonsillar and tonsillo-lingual SCCs compared to those affecting the oral cavity, oropharynx without tonsils, larynx without supraglottis and the hypopharynx. This differential antigen expression may reflect the diverse route of embryologic differentiation followed by the affected regions except those of the tonsils and the supraglottis which show similar antigenic pattern but diverse developmental path. All the other biomarkers tested including p53, collagen XVII and EGFR were detected in the majority of cancers including high grade cases, but did not reveal any significant regional difference. Based on our results oropharyngeal squamous cell carcinomas may not be regarded as one entity. Concerning the oral cavity and the oropharynx, cancers affecting the tonsils (palatine and lingual) show significantly elevated p16(ink4) and Ki67 expression; so as the cancers of the supraglottis compared to the rest of larynx. Consequently, tonsillar and supraglottic cancers show similar biomarker profiles. Correlation of differential biomarker expression with diverse biological behavior in head and neck cancers need further investigations.

Irradiation-induced regulation of plasminogen activator inhibitor type-1 and vascular endothelial growth factor in six human squamous cell carcinoma lines of the head and neck

PURPOSE

It has been shown that plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are involved in neo-angiogenesis. The aim of this study was to investigate the irradiation-induced regulation of PAI-1 and VEGF in squamous cell carcinomas of the head and neck (SCCHN) cell lines of varying radiation sensitivity.

METHODS AND MATERIALS

Six cell lines derived from SCCHN were investigated in vitro. The colorimetric AlamarBlue assay was used to detect metabolic activity of cell lines during irradiation as a surrogate marker for radiation sensitivity. PAI-1 and VEGF secretion levels were measured by enzyme-linked immunosorbent assay 24, 48, and 72 h after irradiation with 0, 2, 6, and 10 Gy. The direct radioprotective effect of exogenous PAI-1 was measured using the clonogenic assay. For regulation studies, transforming growth factor-beta1 (TGF-beta1), hypoxia-inducible factor-1alpha (HIF-1alpha), hypoxia-inducible factor-2alpha (HIF-2alpha), or both HIF-1alpha and HIF-2alpha were downregulated using siRNA.

RESULTS

Although baseline levels varied greatly, irradiation led to a comparable dose-dependent increase in PAI-1 and VEGF secretion in all six cell lines. Addition of exogenous stable PAI-1 to the low PAI-1-expressing cell lines, XF354 and FaDu, did not lead to a radioprotective effect. Downregulation of TGF-beta1 significantly decreased VEGF secretion in radiation-sensitive XF354 cells, and downregulation of HIF-1alpha and HIF-2alpha reduced PAI-1 and VEGF secretion in radiation-resistant SAS cells.

CONCLUSIONS

Irradiation dose-dependently increased PAI-1 and VEGF secretion in all SCCHN cell lines tested regardless of their basal levels and radiation sensitivity. In addition, TGF-beta1 and HIF-1alpha could be partly responsible for VEGF and PAI-1 upregulation after irradiation.

Molecular markers predict outcome in squamous cell carcinoma of the head and neck after concomitant cisplatin-based chemoradiation

Not all patients with squamous cell carcinomas of the head and neck (HNSCC) benefit from concurrent cisplatin-based chemoradiation, but reliable predictive markers for outcome after chemoradiation are scarce. We have investigated potential prognostic biomarkers for outcome in a large group of patients. Ninety-one tumor biopsies taken from consecutive HNSCC patients were evaluated for protein expression on a tissue microarray. Using immunohistochemistry, 18 biomarkers, involved in various cellular pathways were investigated. Univariable and multivariable proportional hazard analyses were performed to investigate associations between each individual marker and outcome. In addition, the global test was used to test all variables simultaneously and selected combinations of markers for an overall association with local control. Univariable analysis showed statistically significant increased relative risks of RB, P16 and MRP2 for local control and MDR1 and HIF-1alpha for overall survival. MRP2, MDR1 and P16 levels were positively associated with outcome whereas RB and HIF-1alpha had a negative relationship. Using Goeman's global testing no combination of markers was identified that was associated with local control. Grouping the markers according to their function revealed an association between a combination of 3 markers (P16, P21 and P27) and outcome (p = 0.05) was found. In the multivariable analysis, MRP2 and RB remained significant independent predictive markers for local control. This study describes the prognostic value of biomarkers for the outcome in patients uniformly treated with concurrent chemoradiation. MRP2 and RB were found to be associated with outcome in patients treated with concurrent chemoradiation.

Quantification of microvessels in canine lymph nodes

Quantification of microvessels in tumors is mostly based on counts of vessel profiles in tumor hot spots. Drawbacks of this method include low reproducibility and large interobserver variance, mainly as a result of individual differences in sampling of image fields for analysis. Our aim was to test an unbiased method for quantifying microvessels in healthy and tumorous lymph nodes of dogs. The endothelium of blood vessels was detected in paraffin sections by a combination of immunohistochemistry (von Willebrand factor) and lectin histochemistry (wheat germ agglutinin) in comparison with detection of basal laminae by laminin immunohistochemistry or silver impregnation. Systematic uniform random sampling of 50 image fields was performed during photo-documentation. An unbiased counting frame (area 113,600 microm(2)) was applied to each micrograph. The total area sampled from each node was 5.68 mm(2). Vessel profiles were counted according to stereological counting rules. Inter- and intraobserver variabilities were tested. The application of systematic uniform random sampling was compared with the counting of vessel profiles in hot spots. The unbiased estimate of the number of vessel profiles per unit area ranged from 100.5 +/- 44.0/mm(2) to 442.6 +/- 102.5/mm(2) in contrast to 264 +/- 72.2/mm(2) to 771.0 +/- 108.2/mm(2) in hot spots. The advantage of using systematic uniform random sampling is its reproducibility, with reasonable interobserver and low intraobserver variance. This method also allows for the possibility of using archival material, because staining quality is not limiting as it is for image analysis, and artifacts can easily be excluded. However, this method is comparatively time-consuming.

Microvessel density >or=60 does not predict for outcome after radiation treatment for locally advanced head and neck squamous cell carcinoma: results of a correlative study from the Radiation Therapy Oncology Group (RTOG) 90-03 Trial

OBJECTIVES

To assess whether microvessel density (MVD), an immunohistochemical marker for tumor vascularity, predicts for radiotherapy (RT) outcome in locally advanced HNSCC patients.

METHODS

A total of 459 patients, enrolled on the RTOG 90-03 trial, had biopsy specimens submitted, and a value for MVD determined, prior to definitive RT. 450 patients were analyzable for this study. Tumor microvessels were stained for factor VIII-related antigen using a standard immunoperoxidase method. The mean number of stained microvessel profiles, from three x200 fields containing the highest MVD (hot spot), was recorded as the MVD. A prospective value of >or=60 was chosen as the threshold for high MVD, tumor vascularity.

RESULTS

The median follow-up for the analyzable patients with MVD assessment was 22.0 months and 79.1 months for all living patients. There were no differences concerning the pretreatment characteristics between those RTOG 90-03 patients with a value for MVD and those without a value for MVD. Thus, the present study cohort possessed comparable characteristics with the entire RTOG 90-03 population. MVD values ranged from 5 to 80, with a median value of 30. Only 37 of 450 (8.2%) patients possessed an MVD >or=60. There were no outcome differences for patients with MVD <60 versus >or=60 on multivariate analysis for time to local-regional failure (P = 0.89), time to distant metastasis (P = 0.80), disease-free survival (P = 0.46), and overall survival (P = 0.39).

CONCLUSIONS

In this large, correlative study, a MVD >or=60, ie, high tumor vascularity, did not predict for outcome in locally advanced head and neck squamous cell carcinoma patients treated with radiotherapy.

Vascular Endothelial Growth Factor Expression Predicts Outcome after Primary Radiotherapy for Head and Neck Squamous Cell Cancer

AIMS

To establish whether the expression of vascular endothelial growth factors (VEGFs) predicts prognosis in patients treated with primary radiotherapy for cancers of the upper aerodigestive tract.

MATERIALS AND METHODS

A retrospective analysis was undertaken of VEGF and VEGF-D expression in tumour tissue in pre-treatment biopsies from 27 patients who had been treated with primary radiotherapy for stage II-IV squamous head and neck carcinomas. Serial sections (4 microm) were cut from formalin-fixed, paraffin-embedded specimens and stained with monoclonal antibodies using standard immunoperoxidase methods. Two independent investigators assessed the staining intensity in a randomised, blind manner. Both negative and positive controls (placenta and/or tonsil) were included in the staining procedure. All patients were followed for a minimum of 5 years, or until death. Local control and overall survival were taken as end points for the comparative analysis between patients whose tumours expressed low levels and those that expressed high levels of the two growth factors. Comparisons were made using the Log-rank test with Kaplan-Meier actuarial survival analysis.

RESULTS

In patients with tumours expressing low levels of VEGF, 5-year local control was seen in 75% compared with 18% for those with high levels; overall survival was 75 and 23%, respectively. For those with low levels of VEGF-D, 5-year local control was 64% compared with 17% for those with high levels; overall survival was 58 and 20%, respectively.

CONCLUSION

Our results suggest that the expression of endothelial growth factors in squamous head and neck cancers may predict outcome after radiotherapy.

Endoglin (CD105) as a prognostic factor in head and neck squamous cell carcinoma

Endoglin (CD105) is a proliferation-associated protein abundantly expressed in angiogenic endothelial cells. Recent studies revealed that CD105 is intensively expressed in tumor vasculature, whereas intratumoral microvessel density (MVD) determined with the use of antibodies to CD105 has been found to be an important prognostic indicator for the outcome in a number of malignancies. In the current study, we investigated endoglin expression and evaluated MVD in 108 patients with head and neck squamous cell carcinoma. Endoglin was intensively expressed in intratumoral blood vessels, whilst lymphatics were rarely positive for CD105. High microvessel density was associated with a more aggressive tumor phenotype, including advanced clinical stage (p = 0.008) and the presence of lymph node metastasis at the time of diagnosis (p = 0.02). When microvessel counts were assessed for their prognostic values (high vs low MVD), there was a statistically significant difference in the overall survival among patients with tumors of the oral cavity and larynx (p < 0.001) and in the disease-free survival among patients with tumors of the lower lip (p = 0.01). The prognostic impact of microvessel density was not dependent on clinical stage or lymph node status. The results of the current study suggest that CD105 is a promising target for tumor imaging and prognosis.

Computer-Assisted Analysis of Biopsy Specimen Microvessels Predicts the Outcome of Esophageal Cancers Treated with Chemoradiotherapy

PURPOSE

A computer-assisted microvessel analysis system was developed to evaluate correlations between the architecture of biopsy specimen microvessels and the outcome for patients with esophageal cancer treated with chemoradiotherapy.

EXPERIMENTAL DESIGN

Biopsy specimens from 51 patients with esophageal cancer (T(2-3), any N, M0) treated with chemoradiotherapy were immunostained with an anti-CD31 antibody and quantified using computerized image analysis. We evaluated the association of several microvessel factors with overall survival, including the ratio of total microvessel perimeter to total tumor area (TP/TA), the tumor hypoxic ratio, and the ratio of total microvessel number to total tumor area (TN/TA). Results from traditional manual microvessel density (MVD) hotspot count and computerized hotspot count were compared and the relation between hotspot MVD count and survival rate was evaluated.

RESULTS

The median follow-up time was 32 months. Both univariate and multivariate analyses revealed that computer-counted hotspot MVD and TN/TA and TP/TA ratios correlated significantly with the outcome of chemoradiotherapy. Kaplan-Meier survival curves showed that patients with high computer-counted hotspot MVDs and high TN/TA and TP/TA ratios had better overall survival rate than patients with low MVDs or ratios (P = 0.025, 0.008, and 0.031, respectively). Combining computer-counted MVD or TN/TA ratio with TP/TA ratio proved more predictive than any single factor. Two researcher-counted hotspot MVDs had no significant relation with outcome.

CONCLUSION

Computer-assisted tumor microvessel analysis is a powerful tool in predicting the outcome for patients with esophageal cancer treated with chemoradiotherapy because intraobserver and interobserver variability is minimized.

Prognostic significance of vascular endothelial growth factor immunohistochemical expression in head and neck squamous cell carcinoma: a meta-analysis

PURPOSE

Vascular endothelial growth factor (VEGF) is considered as a prime mediator of angiogenesis. Various studies examining the relationship between VEGF protein overexpression with the clinical outcome in patients with head and neck squamous cell carcinoma have yielded inconclusive results.

EXPERIMENTAL DESIGN

We conducted a meta-analysis of 12 studies (n = 1.002 patients) that evaluated the correlation between VEGF (detected by immunohistochemistry) and 2-year overall survival. The relation between VEGF and lymph node involvement (11 studies, n = 722) was also examined. Data were synthesized with random effect and fixed effect risk ratios.

RESULTS

The estimated risk of death in 2 years was 1.88-fold higher in the VEGF-positive patients [95% confidence interval, 1.43-2.45; P < 0.001 random effect calculations]. Between-study heterogeneity was nonsignificant (P = 0.15) but larger studies tended to provide more conservative estimates (P = 0.097). VEGF overexpression was not significantly associated with the presence of lymph node metastasis (risk ratio, 1.20; 95% confidence interval, 0.97-1.49; P = 0.087) and there was significant between-study heterogeneity (P = 0.08).

CONCLUSIONS

Although some modest bias cannot be excluded, VEGF positivity seems to be associated with worse overall survival in patients with head and neck squamous cell carcinoma.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Hypoxia-induced tumor angiogenic pathway in head and neck cancer: an in vivo study

Numerous studies indicate the importance of hypoxia-induced pathway in tumor angiogenesis, but in vivo studies examining the importance of this mechanism in prognosis of patients with head and neck squamous cell carcinoma present conflicting results. We performed a retrospective analysis of 81 patients with head and neck squamous cell carcinoma in order to investigate whether hypoxia-inducible factor 1a (HIF-1a) immunohistochemical expression correlates with vascular endothelial growth factor (VEGF) expression and clinicopathologic parameters or prognosis. Our results showed a statistically significant association between HIF-1a and VEGF expression in tumors located in the lower lip and in larynx, but not in those located in the oral cavity. HIF-1a expression had no impact on prognosis, while VEGF expression correlated significantly with adverse prognosis. These findings support the hypothesis that tumor angiogenesis is close related, but not strictly dependent, on the hypoxic conditions of tumor's microenvironment.

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

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

Histological quantitation of tumour angiogenesis

Tumours establish their blood supply via a number of processes in addition to angiogenesis. These include vasculogenesis, vascular remodelling, intussusception and possibly vascular mimicry in certain tumours. The mainstay of the assessment of tumour vascularity has been counting the number of immunohistochemically identified microvessels in vascular hot spots. Nevertheless, several other techniques are available, including Chalkley counting, vascular grade and the use of image analysis systems. Angiogenic activity can furthermore be assessed in histological samples by measuring the molecules involved in the establishment of the tumour vasculature, including angiogenic growth factors and their receptors, cell adhesion molecules, proteases and markers of activated, proliferating, cytokine stimulated or angiogenic vessels, such as CD105. Measuring the maturity of vessels may give an indication of the proportion of the tumour vasculature that is functional. Other reagents that can identify hypoxia-activated pathways are also being developed. The histological assessment of tumour vascularity is mainly used in the research setting but may also have applications in the clinic if appropriate methodology and trained observers perform the studies. Gene arrays may be able to provide an angiogenesis profile. Continued study into the processes involved in generating a tumour blood supply is likely to identify new markers that may be more accurate measures.

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

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

Molecular markers in clinical radiation oncology

Radiation therapy plays a critical role in the management of a majority of patients diagnosed with cancer. Identification of factors that help predict which patients are at risk for relapse within the irradiated field remains an active area of investigation. Although conventional clinical and pathologic factors have been helpful in identifying risk and guiding clinical decision-making for both local and systemic management, there is clearly a need to identify additional prognostic markers, which can aid in refining our treatment strategies and improving outcomes. A substantial amount of research efforts have been devoted to identifying molecular markers for prognostic and therapeutic strategies. The recent emergence of a powerful armamentarium of molecular tools has resulted in rapid expansion of our fund of knowledge and understanding of the molecular biology underlying tumor behavior and response. While a majority of these efforts have been focused on risk factors for metastatic disease and survival, there is a rapidly growing body of literature focused on molecular factors associated with radiation resistance and locoregional failure. In this review, we summarize recent advances and the available literature evaluating molecular markers as they relate to radiation sensitivity of solid tumors. Literature regarding the potential application of expression of genes related to apoptosis, angiogenesis, cell cycle, DNA repair and growth factors will be reviewed. Some of the basic biology and laboratory evidence demonstrating how the marker relates to radiation response and available correlative clinical studies employing these markers as prognostic tools are presented. The majority of molecular markers that have potential clinical significance with respect to radiation sensitivity and local control will be highlighted.

Tumor hypoxia at the micro-regional level: clinical relevance and predictive value of exogenous and endogenous hypoxic cell markers

BACKGROUND AND PURPOSE

Tumor oxygenation is recognized as an important determinant of the outcome of radiotherapy and possibly also of other treatment modalities in a number of tumor types and in particular in squamous cell carcinomas. The hypoxic status of various solid tumors has been related to a poor prognosis due to tumor progression towards a more malignant phenotype, with increased metastatic potential, and an increased resistance to treatment. It has been demonstrated in head and neck cancer that hypoxic radioresistance can be successfully counteracted by hypoxia modifying approaches. The microregional distribution and the level of tumor hypoxia depend on oxygen consumption and temporal and spatial variations in blood supply. It is unclear if severely hypoxic cells can resume clonogenicity when O(2) and nutrients become available again as a result of (treatment related) changes in the tumor microenvironment. Non-terminally differentiated hypoxic cells that are capable of proliferation are important for outcome because of their resistance to radiotherapy and possibly other cytotoxic treatments. Various exogenous and endogenous markers for hypoxia are currently available and can be studied in relation to each other, the tumor architecture and the tumor microenvironment. Use of nitroimidazole markers with immunohistochemical detection allows studying tumor cell hypoxia at the microscopic level. Co-registration with other microenvironmental parameters, such as vascular architecture (vascular density), blood perfusion, tumor cell proliferation and apoptosis, offers the possibility to obtain a comprehensive functional image of tumor patho-physiology and to study the effects of different modalities of cancer treatment.

CONCLUSION

A number of functional microregional parameters have emerged that are good candidates for future use as indicators of tumor aggressiveness and treatment response. The key question is whether these parameters can be used as tools for selection of treatment strategies for individual patients. This requires testing of these markers in prospective randomized clinical trials comparing standard treatment against experimental treatments targeting the relevant microregional constituent.

[Volume-effect in radiation therapy part one: volume-effect and tumour]

Volume is an important parameter of radiation therapy. Local control is inversely related to tumor size and the complication rate increases with the importance of the irradiated volume. Although the effect of irradiated volume has been widely reported since the beginning of radiotherapy, it has been less studied than other radiation parameters such as dose, fractionation, or treatment duration. One of the first organ system in which the adverse effect of increased volume was well defined is the skin. Over the last twenty years, numerous mathematical models have been developed for different organs. In this report we will discuss the relation between irradiated volume and tumor control. In a second article we will study the impact of irradiated volume on radiation adverse effects.

Vascular architecture, hypoxia, and proliferation in first-generation xenografts of human head-and-neck squamous cell carcinomas

PURPOSE

To quantify the physiologic status of human tumor cells in relation to the tumor vasculature.

METHODS AND MATERIALS

Fourteen tumors of 11 first-generation xenograft lines of human head-and-neck squamous cell carcinoma were injected with the hypoxic cell marker pimonidazole, the proliferation marker BrdUrd, and the perfusion marker Hoechst 33342. Consecutive tissue sections were processed with immunohistochemical methods and analyzed with image-analysis techniques.

RESULTS

Three different hypoxic patterns were found: patchy, ribbon-like, and mixed. An image-analysis method was developed to quantify these, and an elongation index (length/width) was calculated for hypoxia. The mean elongation indices ranged from 2.0 to 28.3 and showed a good correlation with the visual scoring of hypoxic patterns. Comparative analysis of hypoxic and proliferating cells in zones around the tumor vasculature showed the presence of both hypoxic and proliferating cells in all zones up to 250 microm from the vessels. The largest coexistence of hypoxic and proliferating cells seemed to occur at 50-100 microm from the vessels.

CONCLUSIONS

The three hypoxic patterns could be quantified by an elongation index, which is an additional parameter that allows distinction of tumors with similar fractions of hypoxic cells. The analysis of hypoxic and proliferating cells as a function of distance from the tumor vasculature indicates that proliferation does occur also at low oxygen tensions.

Expression of transforming growth factor-alpha, epidermal growth factor receptor and platelet-derived growth factors A and B in oropharyngeal cancers treated by curative radiation therapy

BACKGROUND AND PURPOSE

Epidermal growth factor receptor (EGFR) has been implicated in cellular responses to ionizing radiation and represents a major target for current radiosensitizing strategies. We wished to ascertain whether a correlation existed between the expression of EGFR, transforming growth factor-alpha (TGFalpha) and platelet-derived growth factors A and B (PDGF-A and PDGF-B) and treatment outcome in a group of patients with oropharyngeal cancer who had undergone curative radiation therapy. We also assessed the relationship existing between each of the aforementioned proteins and intratumoral microvessel densities (IMD) which have been previously reported (Int J Radiat Oncol Biol Phys 2000;48:17-25.

MATERIALS AND METHODS

Pretherapeutic tumor biopsies from 95 patients were immunohistochemically stained and their immunoreactivities evaluated semi-quantitatively. The statistical analyses included Cox regression for calculating risk ratios of survival endpoints and logistic regression for determining odds ratios for the development of distant metastasis.

RESULTS

Local tumor control as well as disease-free and overall survival were independent of protein expression levels, whereas combined TGFalpha and EGFR immunoreactivities were closely related to IMD (P = 0.003). The expression levels of these two proteins were also correlated to each other (P = 0.015). Expression of PDGF-B occurred in 54% of cases and was associated with an increase in the risk of developing distant metastasis (P = 0.011).

CONCLUSIONS

Tumoral levels of TGFalpha, EGFR and PDGF-A/B are not predictive of radioresponsiveness in oropharyngeal cancers. The association between IMD and immunoreactivity for TGFalpha and EGFR indicates the involvement of these proteins in the promotion of angiogenesis in these tumors. PDGF-B should be further evaluated as a prognostic marker for squamous cell cancer of the head and neck.

Intra-tumoural microvessel density in human solid tumours

Over the last decade assessment of angiogenesis has emerged as a potentially useful biological prognostic and predictive factor in human solid tumours. With the development of highly specific endothelial markers that can be assessed in histological archival specimens, several quantitative studies have been performed in various solid tumours. The majority of published studies have shown a positive correlation between intra-tumoural microvessel density, a measure of tumour angiogenesis, and prognosis in solid tumours. A minority of studies have not demonstrated an association and this may be attributed to significant differences in the methodologies employed for sample selection, immunostaining techniques, vessel counting and statistical analysis, although a number of biological differences may account for the discrepancy. In this review we evaluate the quantification of angiogenesis by immunohistochemistry, the relationship between tumour vascularity and metastasis, and the clinicopathological studies correlating intra-tumoral microvessel density with prognosis and response to anti-cancer therapy. In view of the extensive nature of this retrospective body of data, comparative studies are needed to identify the optimum technique and endothelial antigens (activated or pan-endothelial antigens) but subsequently prospective studies that allocate treatment on the basis of microvessel density are required.

The expression of vascular endothelial growth factor (VEGF) and VEGF-C in early laryngeal cancer: relationship with radioresistance

Angiogenesis is essential for tumour growth and invasion. Vascular endothelial growth factor (VEGF) is a prime mediator of tumour angiogenesis. VEGF-C is a closely related protein that effects lymphatic endothelial cells and may be important in the process of lymphatic metastasis. The purpose of this study was to evaluate the expression of these cytokines in patients with T1 and T2a glottic, squamous cell carcinoma, in comparison with normal epithelial control tissue, to ascertain any association with radioresistance. Twenty-two tumours treated by radiotherapy (13 radiosensitive, nine radioresistant) and seven normal control tissues were studied. The minimum follow-up was 2 years after radiotherapy. Expression of VEGF and VEGF-C was evaluated by immunohistochemistry of formalin-fixed, paraffin-embedded biopsy specimens. Analysis was carried out using a quantitative computer image analyser. Both VEGF and VEGF-C were detectable in tumour and normal control specimens. There was increased expression in tumour specimens of both VEGF (P = 0.03) and VEGF-C (P < 0.001). In addition, the expression of VEGF-C was associated with tumours of higher histological grade (P = 0.021). There was, however, no difference in VEGF and VEGF-C expression between radioresistant and radiosensitive tumours. The expression of VEGF and VEGF-C is increased in early laryngeal squamous cell carcinoma (SCC). However, measuring the expression of these proteins cannot predict radioresistance in this tumour group.

Patterns of proliferation related to vasculature in human head-and-neck carcinomas before and after transplantation in nude mice

PURPOSE

The predictive potential of tumor cell kinetic parameters may be improved when they are studied in relation to other microenvironmental parameters. The purpose of this investigation was to quantitatively categorize human tumor samples according to proliferation patterns. Second, it was examined whether these characteristics are retained after xenotransplantation.

METHODS AND MATERIALS

Fifty tumor samples from head-and-neck cancer patients were immunohistochemically stained for Ki-67 and vessels. Also, parts of the samples were transplanted into nude mice. Tumors were categorized according to previously described patterns of proliferation. Vascular and proliferation patterns were analyzed using an image processing system.

RESULTS

The 50 tumors were categorized into four patterns of proliferation by visual assessment: marginal (6), intermediate (10), random (21), and mixed (12). One tumor could not be classified. These patterns were quantified by calculating the Ki-67 labeling index in distinct zones at increasing distance from vessels yielding good discrimination and significant differences between patterns. The probability of growth after xenotransplantation was significantly higher for tumors with a labeling index and vascular density above the median value compared to tumors with both parameters below the median (82% vs. 35%). Fifty percent of the tumors retained their proliferation patterns after xenotransplantation.

CONCLUSION

The categorization by proliferation pattern previously described by others was reproduced quantitatively and spatially related to the vascular network using a computerized image processing system. The combination of quantitative and architectural information of multiple microenvironmental parameters adds a new dimension to the study of treatment resistance mechanisms. Tumor models representative of the various patterns can be used to further investigate the relevance of these architectural patterns.

Vascular endothelial growth factor: its prognostic, predictive, and therapeutic implications

Since the discovery that cancer development requires the growth of new blood vessels, many investigations have revealed the key molecules in the regulation of new vessel formation. One of the most important of these molecules is vascular endothelial growth factor (VEGF)--an endothelial-cell-specific mitogen and survival factor. VEGF also causes increased vascular permeability and recruits progenitor endothelial cells from the bone marrow. Clinical observations have confirmed that VEGF status is closely associated with the extent of neovascularisation and prognosis in many solid tumours. VEGF status is predictive of resistance to various treatments, including radiotherapy, chemotherapy, and endocrine therapy. Preliminary results also indicate that anti-VEGF treatment suppresses cancer progression without serious toxic effects. Various approaches for the control of cancers involving inhibition of the activity of VEGF are currently being investigated. This review considers the clinical implications of VEGF, particularly its prognostic, predictive, and therapeutic value.

Human papillomavirus positive squamous cell carcinoma of the oropharynx: a radiosensitive subgroup of head and neck carcinoma

BACKGROUND

Epidemiologic evidence points to a connection between viral infection by the human papillomavirus (HPV) and a subgroup of squamous cell carcinoma of the oropharynx. To assess the impact of HPV infection on the response of these tumors toward radiotherapy, the authors retrospectively determined the presence of the virus and the integrity of the viral E2 gene in tumors of patients who have undergone curative irradiation.

METHODS

Paraffin embedded biopsies from 99 patients were analyzed for HPV infection and E2 gene integrity by multiplex PCR. The experimental findings were correlated with clinical characteristics, known risk factors, and treatment outcome.

RESULTS

Fourteen of 99 tumors were HPV positive (11 HPV16, 1 HPV33, 1 HPV35, and 1 HPV45). Human papillomavirus positivity was closely linked to female gender (odds ratio [OR], 5.75; P = 0.004), age older than 56 years (OR, 7.42; P = 0.012), nonsmokers (OR, 21.33; P = 0.00001), and alcohol abstainers (OR, 5.35; P = 0.012). There was an inverse association with p53 nuclear immunoreactivity (OR, 0.06; P = 0.008). The Kaplan-Meier survival estimates showed a better local control (P = 0.050, log-rank) and a better overall survival (P = 0.046, log-rank) for patients with HPV positive tumors. In the multivariate analysis, HPV positivity remained to be associated with a lower risk of local failure (risk ratio [RR], 0.31; P = 0.048). Four of 11 HPV16 positive tumors had a disrupted E2 gene. Only tumors with a disrupted E2 gene manifested local treatment failure.

CONCLUSIONS

Human papillomavirus positivity designates a specific subgroup of oropharyngeal squamous cell carcinomas of the oropharynx that arise preferentially among individuals with no consumption of tobacco and alcohol and that have a favorable outcome attributable to an increased sensitivity toward radiotherapy.

Involvement of the hepatocyte growth factor/scatter factor receptor c-met and of Bcl-xL in the resistance of oropharyngeal cancer to ionizing radiation

The activation of cytoplasmic signal transduction pathways by a number of growth factors and their tyrosine-kinase receptors, including hepatocyte growth factor/scatter factor (HGF/SF) and its receptor c-met, exerts an inhibitory influence on apoptosis induced by ionizing radiation in vitro. The clinical relevance of the aforementioned ligand-receptor pair, of Bcl-xL, which is targeted by HGF/SF/c-met signaling, and of Bcl-2, was assessed by evaluating their predictive and prognostic impact in a cohort of 97 patients with radically irradiated squamous cell cancers of the oropharynx. Immunohistochemical expression of c-met and Bcl-xL was correlated with decreased rates of complete remission of the primary tumor in both the univariate (c-met: P = 0.01; Bcl-xL: P = 0.001) and multivariate analyses. Expression of c-met was, moreover, a significant and independent predictor of impaired local failure-free survival (P = 0.003), disease-free survival (P = 0.003) and overall survival (p = 0.001). Bcl-2 expression was, on the other hand, associated with a favorable outcome, in terms of both local failure-free survival (P = 0.01) and overall survival (P = 0.001). In accordance with in vitro data, c-met and Bcl-xL appear to be involved in the resistance of oropharyngeal cancers to ionizing radiation, and may therefore represent attractive targets for radiosensitization.