Search results for "Tumor Hypoxia"
showing 10 items of 56 documents
Detection and characterization of tumor hypoxia using pO2 histography.
2007
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 ov…
Oxygenation of Mammary Tumors: From Isotransplanted Rodent Tumors to Primary Malignancies in Patients*
1992
The role of oxygen in tumor cell proliferation, radiosensitivity, cytotoxicity of anticancer drugs and hyperthermia treatment has been the subject of a series of investigations (for reviews see Hall, 1988; Teicher et al., 1990, Vaupel et al., 1989a; Vaupel, 1990a,b). Despite the apparent importance of tumor oxygenation, data on pO2 values in solid tumors are mostly derived from experiments on rodents which might not necessarily reflect the variability of the clinical situation. Due to feasible techniques available now, considerable advances have been made in the past few years in the assessment of tumor hypoxia in patients (for reviews see Vaupel et al., 1989a; Vaupel, 1990a). The latter in…
Intratumoral PO2 Histography as Predictive Assay in Advanced Cancer of the Uterine Cervix
1994
Experimental evidence suggests that the hypoxic fraction in a solid tumor may increase its malignant potential and reduce its sensitivity towards nonsurgical treatment modalities such as standard irradiation and certain anticancer agents1–5. However, the clinical importance of tumor hypoxia remains uncertain since valid methods for the routine measurement of intratumoral O2-tensions in patients have so far been lacking.
Oxygen status of malignant tumors: pathogenesis of hypoxia and significance for tumor therapy.
2001
Hypoxic areas are a characteristic property of solid tumors. Hypoxia results from an imbalance between the supply and consumption of oxygen. Major pathogenetic mechanisms for the emergence of hypoxia are (1) structural and functional abnormalities in the tumor microvasculature; (2) an increase in diffusion distances; and (3) tumor- or therapy-associated anemia leading to a reduced O2 transport capacity of the blood. There is pronounced intertumor variability in the extent of hypoxia, which is independent of clinical size, stage, histopathologic type, and grade. Local recurrences have a higher hypoxic fraction than primary tumors. Tumor hypoxia is intensified in anemic patients, especially i…
Lack of Association Between Tumor Hypoxia, Glut-1 Expression and Glucose Uptake in Experimental Sarcomas
2003
Hypoxia is a common phenomenon in experimental and human tumors which not only limits the efficacy of non-surgical treatment modalities such as irradiation and 02-dependent chemotherapy but also affects the long-term prognosis of cancer patients. Numerous studies have clearly demonstrated that patients with more hypoxic tumors have a reduced probability for survival and disease-free survival’. For this reason it might be helpful to non-invasively identify patients with hypoxic malignancies.
Endogenous Hypoxia Markers: Case Not Proven!
2008
The pivotal role of hypoxia within the pathophysiological framework of solid malignant tumors is now considered to be indisputable. The fact that hypoxia can cause resistance to various cancer therapies and promote malignant progression is reflected in its adverse impact on prognosis which is repeatedly shown for various tumor entities. Knowledge in this area is based on direct assessment of the oxygenation status using O2-sensitive microsensors. However, weaknesses of this standard method are its invasiveness and limitation to accessible tumor entities. Hypoxia-inducible factor (HIF)-1α, the master transcriptional regulator of the hypoxic response, as well as certain downstream genes, e.g.…
Evaluation of Oxygen Diffusion Distances in Human Breast Cancer Using Cell Line Specific in Vivo Data: Role of Various Pathogenetic Mechanisms in the…
1988
Radiobiological hypoxia in malignant tumors has been shown to originate (i) from spatial and temporal functional disturbances of tumor microcirculation resulting in a limited convective O2 flux in microregions even in tissue areas exhibiting high vascular densities, and (ii) from morphological abnormalities of the microcirculatory bed leading to a limitation of the diffusive O2 flux. In addition to these pathogenetic mechanisms, systemic factors (anemia, arterial hypoxia) can also play a role in the development of tumor hypoxia.
Cholesterol Starvation and Hypoxia Activate the FVII Gene via the SREBP1-GILZ Pathway in Ovarian Cancer Cells to Produce Procoagulant Microvesicles
2019
AbstractInteraction between the transcription factors, hypoxia-inducible factor (HIF1α and HIF2α) and Sp1, mediates hypoxia-driven expression of FVII gene encoding coagulation factor VII (fVII) in ovarian clear cell carcinoma (CCC) cells. This mechanism is synergistically enhanced in response to serum starvation, a condition possibly associated with tumor hypoxia. This transcriptional response potentially results in venous thromboembolism, a common complication in cancer patients by producing procoagulant extracellular vesicles (EVs). However, which deficient serum factors are responsible for this characteristic transcriptional mechanism is unknown. Here, we report that cholesterol deficien…
Tumor hypoxia and therapeutic resistance
2008
For many years, the identification of tumor hypoxia, its systematic characterization and the assessment of its clinical relevance were not possible due to the lack of methods suitable for the routine measurement of intratumoral oxygen tensions in patients. In the late 1980s, a novel and clinically applicable standardized procedure was established enabling the determination of tumor oxygenation in accessible primary tumors, local recurrences, and metastatic lesions in patients using a computerized polarographic needle electrode system (Vaupel et al. 1991; Hockel et al. 1991). Within a relatively short period of time, the significance of tumor oxygenation for therapy outcome became evident in…
Tumor Oxygenation and Its Relevance to Tumor Physiology and Treatment
2003
For many years, the identification of tumor hypoxia, its systematic characterization and the assessment of its clinical relevance were not possible due to lack of methods suitable for the routine measurement of intratumoral oxygen tensions in patients. In the late 1980s, a novel and clinically applicable standardized procedure was established enabling the determination of the tissue oxygenation status in primary tumors, local recurrences, and metastatic lesions in patients using a computerized polarographic needle electrode system. Within a relatively short period of time, the significance of tumor oxygenation for therapy outcome became evident in numerous experimental and clinical studies.