Randall Johnson

Wallenberg Scholar

Medicine and medical technology

Randall Johnson
Professor of Molecular Physiology and Pathology

Karolinska Institutet

Oxygen deficiency in tumor tissue – improving cancer therapies

There are oxygen-deficient areas in almost all tumors. This impacts an oxygen-sensitive protein, which in turn influences the way the immune system reacts to the cancer. The protein can both impair and improve the body’s defenses, a paradox that Randall Johnson wants to investigate in order to pave the way for better therapies.

Hypoxia – oxygen deficiency – is a common phenomenon in tumors. The fact that certain parts of the tumor have low oxygen levels increases the risk of the cancer spreading, with less chance of survival. This is partly explained by an oxygen-sensitive protein called HIF.

HIF has complex impacts on the cells of the immune system. On the one hand, immune cells (T-cells) are dependent on HIF to fight the cancer, and their function is also stimulated by hypoxia. On the other hand, HIF is present in macrophages, another type of immune cell, which inhibits the impact of T-cells on cancer, thereby making the cancer more aggressive.

Randall Johnson wants to get to the bottom of the paradox, thereby also adding to our knowledge of tumor biology. He then wants to use that knowledge to find strategies for manipulating the sensitivity of the immune system to oxygen, with the aim of improving current and future cancer therapies, and immunotherapies in particular.

Photo: Stefan Zimmerman