pO2 Histograph Research Articles

Efficacy of metadoxil in the treatment of patients with a combination of chronic alcoholic pancreatitis (CAP) and hepatitis (CAH)

Purpose: To evaluate the potential effects of tumor hypoxia induced by afterloading catheter implantation on the effectiveness of brachytherapy in a rat tumor model.Methods and Materials: Afterloading catheters (4) were implanted in subcutaneously growing R1M rhabdomyosarcoma in female Wag/Rij rats. A MicroSelectron (Nucletron) was used for interstitial high-dose-rate irradiation (192Ir). Tumor oxygenation, perfusion, and cell survival were assessed by pO2 histography (Eppendorf), Tc-99m injection, and excision assay, respectively.Results: Tumor perfusion was markedly reduced at 1 h after catheter implantation (33.9 ± 6.0% (SEM, n = 9) of control) and partly recovered after 5 h (61.5 ± 12.2%). At 24 h, the perfusion level reached control values (100.6 ± 25.7%), but was highly variable with some of the tumors showing hardly any recovery at all. Tumor oxygenation showed a similar pattern, but with less recovery. Median pO2 readings were 13.5, 1.2, and 5.3 mm Hg before and at 1 and 24 h after implantation, respectively (7 tumors). The percentages of pO2 readings ≤ 2.5 mm Hg were 18.9%, 55.6%, and 41.3% at these time points. The difference in cell survival after irradiation (10 Gy) at 1 or 24 h after implantation was compatible with a radiobiological oxygen effect.Conclusion: Implantation of brachytherapy afterloading catheters induces an increased level of hypoxia for several hours by disrupting tumor perfusion, causing both a modest degree of direct cell kill and a significant reduction of the radiation effect. This transient hypoxia might be exploited by combining irradiation with properly timed treatments targeting hypoxic cells.

Rolle der Expression von Plasminogenaktivatorinhibitor 1 (PAI-1) in Bezug auf Hypoxie und Onkoproteine beim Zervixkarzinom

Explore the role of plasminogen activator inhibitor-1 (PAI-1) in cervical cancer and its relationship to hypoxia and the expression of p53, Ku70/80, and cyclin D1. The expression of PAI-1, cyclin D1, and p53, together with tumor oxygenation, were determined in 43 consecutive patients suffering from localized cervical carcinoma. Oncoprotein expression was determined by immunohistochemistry. Tumor oxygenation was measured using a polarographic probe system, "pO2 histography." PAI expression was considered negative in 32.6% and overexpressed in 18.6% of cases. Cyclin D1 showed a median expression of 5.0 (range 0-70). We observed a positive association between PAI expression and altered p53 (p = 0.049) and cyclin D1 (p = 0.020). An inverse association was detected between PAI and Ku70/80 expression (p = 0.042). Cyclin D1 staining increased according to tumor volume (r = 0.314, p = 0.009). We did not observe a significant association between PAI and hypoxia or other clinicopathological parameters. The present results show that PAI-1 overexpression is associated with nonhomologous end-joining DNA repair down-regulation (low Ku70/80 expression) and with increased p53 and cyclin D1 expression, and they suggest that PAI-1 plays a role in the tumor behavior in cervical carcinoma.

Detection and Characterization of Tumor Hypoxia Using pO2 Histography

Data from 125 studies describing the pretreatment oxygenation status as measured in the clinical setting using the computerized Eppendorf pO2 histography system have been compiled in this article. Tumor oxygenation is heterogeneous and severely compromised as compared to normal tissue. Hypoxia results from inadequate perfusion and diffusion within tumors and from a reduced O2 transport capacity in anemic patients. The development of tumor hypoxia is independent of a series of relevant tumor characteristics (e.g., clinical size, stage, histology, and grade) and various patient demographics. Overall median pO2 in cancers of the uterine cervix, head and neck, and breast is 10 mm Hg with the overall hypoxic fraction (pO2 <or= 2.5 mm Hg) being approx. 25%. Metastatic lesions do not substantially deviate from the oxygenation status of (their) primary tumors. Whereas normal tissue oxygenation is independent of the hemoglobin level over the range of 8-15 g/dL, hypoxia is more pronounced in anemic patients and above this range in some cancers. Identification of tumor hypoxia may allow an assessment of a tumor's potential to develop an aggressive phenotype or acquired treatment resistance, both of which lead to poor prognosis. Detection of hypoxia in the clinical setting may therefore be helpful in selecting high-risk patients for individual and/or more intensive treatment schedules.

The Impact of Complement Activation on Tumor Oxygenation During Photodynamic Therapy†

The response to photodynamic therapy (PDT) mediated by photosensitizer Photofrin was examined with Lewis lung carcinomas growing in either complement-proficient C57BL/6 (B6) or complement-deficient complement C3 knockout (C3KO) mice. The results reveal that Photofrin-PDT was more effective in attaining cures of tumors in C3KO than in B6 hosts. Colony-forming ability of cells from tumors excised immediately after Photofrin-PDT confirmed that the direct cell killing effect was more pronounced in C3KO than in B6 hosts. In contrast, PDT mediated by photosensitizer benzoporphyrin derivative (BPD) produced higher cure rates of tumors in B6 hosts than those in C3KO hosts. Determination of tumor C3 levels by ELISA showed that Photofrin-PDT induced markedly more pronounced complement activation than BPD-PDT. Measurements of tumor oxygen tension immediately after PDT by Eppendorf pO2 histograph showed that Photofrin-PDT induced a marked decline in the oxygenation of tumors growing in B6 mice that was much less pronounced in C3KO hosts. With BPD-PDT the oxygen tensions in tumors in B6 and C3KO hosts decreased to a similar extent. This study indicates that complement activation in PDT-treated tumors that varies with different photosensitizers is an important determinant of tumor oxygen limitation effects directly associated with photodynamic action.

PO polarography, contrast enhanced color duplex sonography (CDS), [18F] fluoromisonidazole and [18F] fluorodeoxyglucose positron emission tomography: validated methods for the evaluation of therapy-relevant tumor oxygenation or only bricks in the puzzle of tumor hypoxia?

BackgroundThe present study was conducted to analyze the value of ([18F] fluoromisonidazole (FMISO) and [18F]-2-fluoro-2'-deoxyglucose (FDG) PET as well as color pixel density (CPD) and tumor perfusion (TP) assessed by color duplex sonography (CDS) for determination of therapeutic relevant hypoxia. As a standard for measuring tissue oxygenation in human tumors, the invasive, computerized polarographic needle electrode system (pO2 histography) was used for comparing the different non invasive measurements.MethodsUntil now a total of 38 Patients with malignancies of the head and neck were examined. Tumor tissue pO2 was measured using a pO2-histograph. The needle electrode was placed CT-controlled in the tumor without general or local anesthesia. To assess the biological and clinical relevance of oxygenation measurement, the relative frequency of pO2 readings, with values ≤ 2.5, ≤ 5.0 and ≤ 10.0 mmHg, as well as mean and median pO2 were stated. FMISO PET consisted of one static scan of the relevant region, performed 120 min after intravenous administration. FMISO tumor to muscle ratios (FMISOT/M) and tumor to blood ratios (FMISOT/B) were calculated. FDG PET of the lymph node metastases was performed 71 ± 17 min after intravenous administration. To visualize as many vessels as possible by CDS, a contrast enhancer (Levovist®, Schering Corp., Germany) was administered. Color pixel density (CPD) was defined as the ratio of colored to grey pixels in a region of interest. From CDS signals two parameters were extracted: color hue – defining velocity (v) and color area – defining perfused area (A). Signal intensity as a measure of tissue perfusion (TP) was quantified as follows: TP = vmean × Amean.ResultsIn order to investigate the degree of linear association, we calculated the Pearson correlation coefficient. Slight (|r| > 0.4) to moderate (|r| > 0.6) correlation was found between the parameters of pO2 polarography (pO2 readings with values ≤ 2.5, ≤ 5.0 and ≤ 10.0 mmHg, as well as median pO2), CPD and FMISOT/M. Only a slight correlation between TP and the fraction of pO2 values ≤ 10.0 mmHg, median and mean pO2 could be detected. After exclusion of four outliers the absolute values of the Pearson correlation coefficients increased clearly. There was no relevant association between mean or maximum FDG uptake and the different polarographic- as well as the CDS parameters.ConclusionCDS and FMISO PET represent different approaches for estimation of therapy relevant tumor hypoxia. Each of these approaches is methodologically limited, making evaluation of clinical potential in prospective studies necessary.

Predictive factors in advanced head and neck cancer treated by radio-chemotherapy and hypoxia modification

6085 Background: Anemia and tumor hypoxia are known factors for resistance to radio-chemotherapy (RT-CT). In a previous report we have suggested that spinal cord stimulation (SCS) can modify tumor oxygenation and regional blood flow in head and neck cancer (HNC). The aim of the present prospective study was to test the predictive value of pO2 measurement in HNC treated by RT-CT and hypoxia modification using SCS. Methods: Twelve male patients with advanced HNC were analyzed. Stage IVb-IVa: 8–4; mean age 58 + 7.6 years (46–70). Scheduled therapy was hyperfractionated RT (120 cGy/fraction, two fractions/day, total dose 81.6 Gy) from a Co- 60 source, and tegafur 800 mg/day. SCS devices were placed before RT-CT under local anesthesia. During treatment, SCS was connected from 20–30 min before to 20–30 min after each radiotherapy session. Before treatment, they were assessed: Hemoglobin levels and tumor oxygenation pre-SCS and pos-SCS (measured by a polarographic probe system ‘pO2 Histograph‘), expressed as median-pO2, and the fraction of pO2 values less than 5 mmHg (HF5) and less than 2.5 mmHg (HF2.5). Correlations were assessed using Pearson and Spearman tests, and actuarial survival using Kaplan-Meier estimates and Log-rank test. Results: Hemoglobin levels were correlated with oxygenation pre-SCS and pos-SCS: median-pO2 (p=0.005 and p=0.011), HF5 (p=0.048 and p=0.005) respectively. Anemia was associated with more advanced stage (IVb vs IVa, p=0.022), higher HF5 pos-SCS (p=0.028) and lower disease-free survival (p=0.019). The HF2.5 pos-SCS was adversely correlated with the 2 years actuarial: disease-free survival (p=0.027), cause-specific survival (p=0.008) and overall survival (p=0.008). HF2.5 was also correlated with hematocrit (p=0.044). Conclusions: Low hemoglobin levels and anemia are associated with more hypoxic and more advanced tumors. Pre-treatment tumor hypoxia (assessed by the fraction of pO2 values less than 2.5 mmHg during-SCS) is a strong predictive factor for survival in advanced HNC. Patients with highly hypoxic tumors should be selected for more aggressive treatments. Partially supported by: Grant ‘FUNCIS: PI 31–98‘. Scientific supervision was carried out by GICOR. No significant financial relationships to disclose.

Contrast-Enhanced Color Duplex Sonography (CDS): an Alternative for the Evaluation of Therapy-Relevant Tumor Oxygenation?

To evaluate the predictive value of radiotherapeutically relevant tumor hypoxia by contrast-enhanced color duplex sonography (CDS). The objectification was based on pO2 histography. 25 patients with metastatic neck lymph node from a primary squamous carcinoma of the head and neck were examined. To visualize as many vessels as possible, a contrast enhancer (Levovist®, Schering Corp., Germany) was administered. Horizontal and longitudinal sonographic scans with a thickness of 5 mm were performed on the metastatic neck lymph node. Color pixel density (CPD) was defined as the ratio of colored to gray pixels in a region of interest. It represents the extent of vascularization in the investigated slice. To assess the biological and clinical relevance of oxygenation measurement, the relative frequency of pO2 readings ≤2.5, 5.0, and 10.0 mmHg, as well as mean and median pO2, were documented. In order to investigate the degree of linear association, the Pearson correlation coefficient was calculated. Moderate (|r| > 0.5) to high (|r| > 0.7) correlation was found between the CPD and the parameters of hypoxic fraction (pO2 readings with values ≤5.0 and 10.0 mmHg, as well as mean and median). There was only a slight correlation between CPD and the fraction of pO2 values ≤2.5 mmHg (r = −0.479). CPD represents the mean degree of vascularization. As a noninvasive measurement, this method seems feasible for evaluating the state of global oxygenation in superficial tumors. Nevertheless, this method is limited through its deficiency in describing the vascular heterogeneity of tumors.

The Interactions of Polarographic Measurements of Oxygen Tension and Histological Grade in Human Glioma

The purpose of this study is to investigate the implications of hypoxia and histological grade for survival in patients with gliomas. Tissue oxygen tension was measured intraoperatively using an Eppendorf pO2 Histograph. Survival was calculated from the date of the Eppendorf study to the date of last follow-up. Univariate analysis was performed stratifying patients by patient gender, type of anesthesia used, histological grade, extent of surgery, and patient age. Lastly univariate analysis was performed on the cohort after dichotomizing the median pO2 at 2.0 mmHg, 5.1 mmHg, and 10.0 mmHg. From March of 1996 to June of 1999, 25 patients were entered into this prospective trial. Two patients were excluded from analysis because polarographic measurements included normal brain tissue as well as tumor. Thus for analysis we included 13 patients with high grade gliomas (HGG) and 10 with low grade gliomas (LGG). The median tumor oxygen pressure for the entire cohort was 5.1 mmHg. Higher grade (P=0.0012) was prognostic for poorer survival. Patients were then stratified into groups with a median tumor oxygen tensions either above or below 2.0 mmHg, 5.1 mmHg, and 10.0 mmHg; there was no significant difference found in overall survival. Although histological grade was prognostic for survival, hypoxia, represented as the median tumor oxygen tension, was not a significant independent prognostic indicator of survival in this small and heterogeneous series of patients.

Local physiological changes during photodynamic therapy

Herein an overview is provided of the causes, consequences, and significance of photodynamic therapy (PDT)-mediated effects on tumor oxygenation and blood flow during illumination. Techniques particularly valuable to this research have included tissue oxygen tension measurement by the Eppendorf pO2 Histograph; spatial quantification of hypoxia by EF3 and EF5; and tissue oxygenation/blood flow monitoring by diffuse reflectance/correlation spectroscopy. Severe hypoxia was measured in vivo during PDT and is shown to be a consequence of photochemical oxygen consumption and/or compromised vascular perfusion. Oxygen depletion can be controlled by treatment regimen, occurs in a spatially-definable pattern, and is therapy-limiting. PDT-induced changes in tumor oxygenation during illumination are correlated with outcome. In PDT-treated tissues, blood flow also is determined by treatment regimen and correlates with treatment response. Photodynamic therapy creates distinct, measurable changes in tumor oxygen and blood flow during illumination. These physiological changes may ultimately affect treatment efficacy.

Fluence rate as a modulator of PDT mechanisms

Molecular oxygen in the tissue to be treated by photodynamic therapy (PDT) is critical for photodynamic cell killing. The fluence rate of PDT light delivery has been identified as an important modulator of tissue oxygenation and treatment outcome. This article provides supporting evidence for the role of fluence rate in PDT and discusses the underlying mechanisms. Intratumoral pO2 was measured polarographically in murine tumors before and during PDT light treatment using the Eppendorf pO2 Histograph. Tumor response as a function of fluence rate and fluence was also assessed in murine tumor models. Changes in vascular permeability as a function of fluence rate were determined in murine tumors by measuring tumor uptake of fluorescent beads (200 nm diameter). Severe oxygen depletion is shown to occur within seconds of illumination at a fluence rate of 75 mW/cm2 in radiation-induced fibrosarcoma (RIF) tumors photosensitized with AlPcS2. This effect was reversible and consistent with photochemical oxygen depletion, which has been shown by us and others to be fluence rate dependent. It is demonstrated that fluence rate affects the PDT tumor response in the Colon 26 tumor model, high fluence rate diminishing or even totally inhibiting tumor control, low fluence rate promoting tumor control. The influence of fluence rate is not restricted to cytocidal effects, but can also be seen in sublethal conditions such as vascular permeability. Fluence rate of PDT light delivery exerts far-reaching control upon treatment outcome through its oxygenation modulating properties and possibly other mechanisms yet to be identified. This has been shown to be true in the preclinical and clinical setting. Further development of in situ dosimetry will be necessary to take full advantage of these discoveries.

Evaluation of tumor oxygenation by color duplex sonography: A new approach

Description of a new noninvasive method for the evaluation of tissue oxygenation in head and neck cancer. Prospective nonrandomized controlled study in an academic medical center on 20 patients with neck metastases of head and neck cancer. Metastases were investigated using color duplex sonography and pO2 histography. The vascularization in sonography was quantitatively evaluated by color pixel density and compared to the pO2 values of the same nodes. The correlation between vascularization and flow velocity was 0.71. For the mean/median pO2 -values and for the pO2 readings <10.0 mmHg correlations were r = 0.65 / 0.76 and 0.71. This sonographic method allows a safe and reliable evaluation of oxygenation in metastases of head and neck cancer. The new approach is an alternative to pO2 histography and may play a future role in the planning of radiotherapy in the neck.

Treatment-Induced Changes in Tumor Oxygenation Predict Photodynamic Therapy Outcome

Photodynamic therapy (PDT) requires oxygen to cause tumor damage, yet therapy itself can deplete or enhance tumor oxygenation. In the present work we measured the PDT-induced change in tumor oxygenation and explored its utility for predicting long-term response to treatment. The tissue hemoglobin oxygen saturation (SO(2)) of murine tumors was noninvasively measured by broadband diffuse reflectance spectroscopy. In initial validation studies, the oxyhemoglobin dissociation curve for mouse blood was accurately recreated based on measurements during deoxygenation of a tissue phantom of mouse erythrocytes. In vivo studies exhibited excellent correlation between carbogen-induced changes in SO(2) and pO(2) of radiation-induced fibrosarcoma tumors measured by reflectance spectroscopy and the Eppendorf pO(2) histograph, respectively. In PDT studies radiation-induced fibrosarcoma tumor SO(2) was measured immediately before and after Photofrin-PDT (135 J/cm(2), 38 mW/cm(2)). Animals were subsequently followed for tumor growth to a volume of 400 mm(3) (time-to-400 mm(3)) or the presence of tumor cure (no tumor growth at 90 days after treatment). In animals that recurred, the PDT-induced change in tumor SO(2), i.e., relative-SO(2) (SO(2) after PDT/SO(2) before PDT) was positively correlated with treatment durability (time-to-400 mm(3)). The predictive value of relative-SO(2) was confirmed in a second group of animals with enhanced pre-PDT oxygenation due to carbogen breathing. Furthermore, when all of the animals were considered (those that recurred and those that were cured) a highly significant association was found between increasing relative-SO(2) and increasing probability of survival, i.e., absence of recurrence. As independent variables, the SO(2) after PDT, the pre-PDT tumor volume, and light penetration depth all failed to predict response. As an independent variable, the SO(2) before PDT demonstrated a weak negative association with treatment durability; this association was driven by a correlation between decreasing pre-PDT SO(2) and increasing relative-SO(2). These data suggest that monitoring of PDT-induced changes in tumor oxygenation may be a valuable prognostic indicator.

The interactions of polarographic measurements of oxygen tension and histological grade in human glioma and surrounding peritumoral brain tissue

Purpose/Objective: Hypoxia has been shown to be prognostic for survival in several malignancies. We and others showed previously that the extent of hypoxia correlated with higher histological grade in patients with primary brain tumors. Here we investigated the interaction between hypoxia, measured intraoperatively using an Eppendorf pO2 Histograph, and histological grade of patients with gliomas and examined the implications of these factors for the survival of the patients.

131 Pharmacodynamic analysis of apoptosis and anti-vascular activity in GIST patients treated with Imatinib

To investigate the effects of texaphyrins on the oxygenation of EMT6 mouse mammary tumors in Balb/c Rw mice. Texaphyrins are synthetic, porphyrin-like molecules capable of stably coordinating lanthanide and nonlanthanide metals. Metallotexaphyrin compounds containing gadolinium (MGd), lutetium (MLu), europium (Eu-Tex), dysprosium (Dy-Tex), and manganese (Mn-Tex) were evaluated.Tumor oxygenation was measured using an Eppendorf pO2 histograph when tumors, implanted intradermally in the rear dorsum, reached 150–200 mm3. Oxygen measurements were also made in the leg muscle of tumor-bearing mice, to determine whether changes in oxygenation occurred in nontumor tissue.Motexafin gadolinium (Xcytrin, MGd) seems to be an effective modulator of tumor oxygen tension. The mean of the median tumor pO2 6 hours after injection of MGd was 8.0 ± 2.4 mm Hg. The control value was 1.5 ± 0.4 mm Hg. The oxygen levels within EMT6 tumors were shifted significantly toward higher oxygen tensions 6–8 hours after i.v. injection of 40 μmol/kg MGd, thereby reducing the percentage of severely hypoxic readings (MGd, 6 hours: 44.6 ± 4.3% <2.5 mm Hg; Control: 69.4 ± 3.0% <2.5 mm Hg). There was no significant change in the oxygenation of the leg muscle after MGd treatment. Eu-Tex and Mn-Tex increased the tumor oxygenation to a much lesser degree than MGd. MLu, Dy-Tex, and the vehicle (a 5% mannitol solution) did not modulate tumor oxygenation.MGd is an effective modulator of tumor oxygenation. The central metal composition of texaphyrin compounds is an important determinant of the effect of the texaphyrins on tumor oxygenation.

Oxygenation of tumor recurrences following fractionated radiotherapy of primary tumors. Studies on the rhabdomyosarcoma R1H of the rat.

Tumor oxygenation is well recognized as a major factor of tumor response to radiotherapy. In this respect, a number of studies have examined the response of primary tumors, whereas little is known about the oxygenation of tumor recurrences after radiotherapy. It was the aim of this study to investigate the oxygenation of tumor recurrences after preceding irradiation of the primary tumor. Tumor oxygenation in primary tumors and recurrences of rat rhabdomyosarcomas R1H was measured by using pO(2) probes and Eppendorf pO(2) histography. Primary tumors were irradiated at a (60)Co radiotherapy facility with a total dose of 75 Gy, given in 30 fractions over 6 weeks. Oxygenation was measured in R1H tumors before and directly after completion of irradiation. In R1H recurrences oxygenation was determined, when they reached the same size as the previously treated primary tumors (V(o) = 3.1 +/- 0.5 cm(3)). Additionally, tumor microvessel density and the intercapillary distance of tumor blood vessels were determined on histological sections using a counting grid. Tumor oxygenation in R1H recurrences was significantly lower when compared to primary R1H tumors. In primary tumors a median pO(2) of 17 +/- 7 mmHg was measured. By contrast, the median pO(2) in R1H recurrences was only 5 +/- 5 mmHg (p < 0.05). The high frequency of pO(2) values < 5 mmHg indicated that R1H recurrences were significantly more hypoxic (58 +/- 5%) in comparison to primary tumors (22 +/- 4%). The histological sections of the R1H recurrences showed a higher heterogeneity in their tissue structure than primary nonirradiated tumors. The morphometric studies demonstrated a reduced microvessel density (91 +/- 21/9.04 mm(2) in the tumor periphery; p = 0.0001) compared with recurrent tumors (68 +/- 26) and an enhanced mean distance of tumor blood vessels, especially in the center of the R1H recurrences (184 +/- 20 vs. 243 +/- 70 mm; p = 0.0001). In R1H rhabdomyosarcomas tumor oxygenation in recurrent tumors following radiation therapy is significantly lower than in primary tumors. This observation has to be taken into account in cases of tumor recurrences where repeated radiotherapy, chemotherapy or combined treatment modalities are used.

Erythropoietin-induced reduction of hypoxia before and during fractionated irradiation contributes to improvement of radioresponse in human glioma xenografts

Purpose Our study investigated the influence of recombinant human erythropoietin (rHuEPO) treatment, inducing raised hemoglobin levels in nonanemic mice, on intratumor oxygenation before and during fractionated irradiation. Furthermore, the consequences of rHuEPO administration on tumor response to fractionated radiotherapy (RT) were evaluated. Methods and materials Experiments were performed on two human malignant glioma (GBM Nan1 and U87) xenografted in nude mice. RHuEPO was daily delivered (0.3 IU/g/day, 5 days/week). Tumor hypoxia was assessed before (T1) and during (T6) fractionated irradiation using (1) pO 2-Histograph (Eppendorf, Hamburg, Germany) and (2) the EF5-binding assay. Vascular density was determined using type IV collagen immunostaining. To assess RT efficacy, the irradiation schedule was 20 fractions of 2 Gy, once daily, 5 days/week over 4 weeks. Results At T1, hemoglobin levels in rHuEPO-treated mice were significantly increased. Percentage of pO 2 values <2.5 mm Hg was reduced in rHuEPO-treated tumors as compared with control groups (37.1 ± 19.1% vs. 58.5 ± 27.0%; p = 0.009 for GBM Nan1; 81.6 ± 13.4% vs. 91.5 ± 8.3%; p = 0.035 for U87). The decrease of viable hypoxic tumor cells fraction after rHuEPO was confirmed by the EF5-binding assay. Vascular density was not altered after rHuEPO treatment. At T6, rHuEPO reduced the hypoxic fraction by about 20% ( p = 0.036 and p = 0.171) in GBM Nan1 and U87 irradiated tumors. RHuEPO did not influence tumor growth by itself. RT alone or combined with rHuEPO induced a significant tumor growth delay. Finally, rHuEPO significantly enhanced RT efficacy ( p = 0.012 in GBM Nan1 and p = 0.037 in U87), resulting in radiopotentiation ratios of 1.21 and 1.54 for respective models. Conclusions Our results indicate that rHuEPO, by enhancing blood oxygen–carrying capacity, decreases intrinsic tumor hypoxia and maintains its effect during fractionated irradiation in malignant glioma xenografts. Therefore, rHuEPO contributes to radiosensitize these tumors.

Tumour oxygenation assessed by 18F-fluoromisonidazole PET and polarographic needle electrodes in human soft tissue tumours.

The aim of the study was to identify hypoxia in human soft tissue sarcomas (STS) by PET scanning using the hypoxia marker [18F]-fluoromisonidazole ([18F]FMISO) and invasive oxygen sensitive probes (Eppendorf pO2 Histograph, Germany). Thirteen patients with tumours suspected to be STS were examined by [18F]FMISO PET scanning, and eleven of these patients completed a set of Eppendorf pO2 Histograph measurements following the scanning. By histopathological diagnosis, seven tumours were shown to be STS and six tumours were benign. Ratios between tumour and muscle radioactivity and time activity curves for tumours and muscle tissue were examined in defined regions of interest. Only two malignant tumours showed [18F]FMISO uptake in higher amounts than muscle tissue over time. Hypoxia was present in both benign and malignant tumours as measured by the oxygen electrode method. [18F]FMISO PET in our setting seemed not to be feasible for the detection of tumour hypoxia in human soft tissue tumours. Neither did it reflect the extent of hypoxia as determined with the oxygen electrode measurements.

Anemia in cervical cancers: Impact on survival, patterns of relapse, and association with hypoxia and angiogenesis

Purpose The prognostic impact of anemia in cervical cancers is well established. We have investigated the impact of anemia on prognosis and patterns of relapse in cervical cancers. Furthermore, we analyzed the relationship between anemia, tumor hypoxia, and angiogenesis. Methods and materials Eighty-seven patients (mean age 58 years) with squamous cell cancer of the cervix (Stage IIB: n = 19; Stage IIIB: n = 59; Stage IVA: n = 9) were prospectively enrolled in the study from 1995 through 1999. Patients underwent definitive radiotherapy with a combination of external beam radiotherapy (45–50.4 Gy) and high-dose-rate brachytherapy (5 × 7 Gy). Tumor oxygenation was measured with the Eppendorf pO 2-histograph before radiotherapy and after 19.8 Gy. Angiogenesis was determined by measuring the microvessel density in pretreatment biopsies in 46 patients. The impact of tumor oxygenation (at 0 Gy and 19.8 Gy), hemoglobin (hb) level (at 0 Gy and 19.8 Gy), angiogenesis and clinical parameters on survival and relapse was investigated. Results The 3-year overall survival rate (after a median follow-up of 42 months) was 57% for the whole group of patients, 72% for Stage IIB, 60% for Stage IIIB, and 22% for Stage IVA. The presence of pretreatment anemia had a significant impact on the relapse rate. However, the midtherapy hb level (at 19.8 Gy) had the strongest impact on local failure rate and survival: 3-year local failure rate was 6% in 20 patients with a hb > 13 g/dL at 19.8 Gy, 15% in 47 patients with an hb between 11 and 13 g/dL, and 67% in 20 patients with an hb < 11 g/dL, p = 0.0001. This was associated with a significant impact on the 3-year overall survival, 79% vs. 64% vs. 32%. Twenty-three tumors were poorly oxygenated at both measurements (oxygen pressure [median pO 2] < 15 mm Hg before therapy and at 19.8 Gy). This group had a significantly lower 3-year overall survival as compared with patients with high pO 2 before and/or at 19.8 Gy (38% vs. 68%, p = 0.02), and these poorly oxygenated tumors had also a significantly increased microvessel density. In a multivariate model, the midtherapy hb level maintained an overwhelming impact on local failure rate and survival. Conclusions Hemoglobin level during radiotherapy was the strongest prognostic factor for local control and survival. We could further identify a poor prognostic subgroup with persisting hypoxia during radiotherapy, low hb levels, and increased angiogenesis. According to these findings, an association between anemia, poor tumor oxygenation, and angiogenesis is likely.

Fibroblast growth factors (FGFS) increase breast tumor growth rate, metastases, blood flow, and oxygenation without significant change in vascular density.

Breast tumors expressing no detectable FGFs (MCF-7) were compared with tumors transfected with FGF4 or FGF1 (FGF4/MCF-7 or FGF1/MCF-7), and with MDA-MB-435, which produce endogenous FGF2. Tumor blood flow was measured by 133Xe diffusion, oxygen distribution was measured by Eppendorf pO2 histography, and vascular density was measured by CD31 staining. Tumors that overexpress angiogenic factors grew at a rate far exceeding that of MCF-7. The FGF producing tumors also had much higher metastatic rates to lung. Tumor blood flow was significantly higher in the two FGF-transfected xenografts compared with the parent MCF7. Median tumor pO2 was also higher, and tumor oxygenation was preserved even for large tumors. The vascular density as determined by CD31 staining, however, was not markedly increased in tumors overexpressing angiogenic factors. We found that angiogenic factors preserve and augment neovascular function, thus facilitating tumor growth and progression.

Expression of hypoxia-inducible factor-1α in cervical carcinomas: correlation with tumor oxygenation

Purpose: To investigate the relations between hypoxia-inducible factor-1 (HIF-1), tumor oxygenation, and clinical correlates in patients with locally advanced carcinoma of the uterine cervix.Methods and Materials: Biopsies from 42 patients with invasive cervical carcinoma and previous polarographic O2 measurements were assessed for the expression of HIF-1α using digitized microscopic imaging and analysis.Results: The HIF-1α expression levels ranged from <0.1% to 10.7% of the total tumor area; the positive staining was localized exclusively to the nuclei. Three distinct arrangement patterns of HIF-1α-positive cells in relation to blood vessels were identified using spatial image mapping: (1) most HIF-1α-positive cells were located within the typical oxygen diffusion distance in tissue (≤150 μm to the nearest blood vessel); (2) most HIF-1α-positive cells were located in the vicinity (≤60 μm) of the blood vessels; and (3) no apparent spatial relationship was found between HIF-1α-positive cells and blood vessels. A statistically significant association was found between HIF-1α expression and tumor oxygenation (Spearman correlation coefficient = 0.4, p <0.01), as determined with the Eppendorf pO2 histograph. No correlation was found between the level of HIF-1α expression and patient outcome, using disease-free survival as the end point.Conclusion: Our results suggest that HIF-1α expression may represent a useful biologic marker for hypoxia in uterine cervical cancer.