Tumor hypoxia is a common feature of solid malignancies and occurs when tumors outgrow their chaotic vasculature. An increased oxygen demand leads to decreased oxygen tension at increasing distances from these vessels. Hypoxic cells are resistant to radiotherapy because oxygen is needed to fix the damage to the DNA induced by radiation. Recently, it has become clear that hypoxia also influences the tumor microenvironment, leading to decreased infiltration of immune cells with an anti-tumor function, while immune cells with a pro-tumor function are more present. This leads to increased resistance to novel immunotherapies. With the goal of optimizing current radio- and immunotherapies we investigated the reduction of tumor hypoxia by the pharmacological inhibition of oxygen consumption, thereby normalizing the oxygen concentration in the tumor tissue. Furthermore, we explored the visualization of the immunosuppressive microenvironment by SPECT/CT imaging of the endogenous hypoxia marker CAIX.
Daan Boreel (1993) obtained his Master's degree in Biology from Leiden University in 2018. In 2019, he began his PhD program in the departments of Radiotherapy and Nuclear Medicine. He is currently working as a postdoctoral researcher in the Department of Nuclear Medicine.