Bussink, J., Kaanders, J. H. A. M., Strik, A. M., Vojnovic, B. and van der Kogel, A. J. Optical Sensor-Based Oxygen Tension Measurements Correspond with Hypoxia Marker Binding in Three Human Tumor Xenograft Lines.

Hypoxia has a negative effect on the outcome of radiotherapy and surgery and is also related to an increased incidence of distant metastasis. In this study, tumor pO₂ measurements using a newly developed time-resolved luminescence-based optical sensor (OxyLite™) were compared with bioreductive hypoxia marker binding (pimonidazole). Single pO₂ measurements per tumor were compared to hypoxia marker binding in tissue sections using image analysis. Both assays were performed in the same tumors of three human tumor lines grown as xenografts. Both assays demonstrated statistically significant differences in the oxygenation status of the three tumor lines. There was also a good correlation between hypoxia marker binding and the pO₂ measurements with the OxyLite™ device. A limitation of the OxyLite™ system is that it is not yet suited for sampling multiple sites in one tumor. An important strength is that continuous measurements can be taken at the same position and dynamic information on the oxygenation status of tumors can be obtained. The high spatial resolution of the hypoxia marker binding method can complement the limitations of the OxyLite™ system. In the future, a bioreductive hypoxic cell marker for global assessment of tumor hypoxia may be combined with analysis of temporal changes in pO₂ with the OxyLite™ to study the effects of oxygenation-modifying treatment on an individual basis.