Did you know that cancer is responsible for about 1 out of every six deaths worldwide? This staggering statistic means that cancer claims more lives than AIDS, tuberculosis, and malaria combined. Shockingly, it currently holds the position of being the second leading cause of death on a global scale, following cardiovascular diseases.

The National Cancer Institute defines cancer as a “disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body.”

The relationship between oxygen and cancer is a bit more complex and has been the subject of decades of research.

So, what’s the role of oxygen? 

When you inhale, oxygen enters the lungs and then travels through the bloodstream, nourishing cells across the body. Cancer cells also need oxygen to survive and that’s why tumors form new blood vessels (angiogenesis). As tumors grow rapidly, they outgrow the oxygen supply. However, this doesn’t always hinder their growth. Research indicates that certain cancers can thrive and resist treatment in oxygen-deprived conditions.

Your body has an oxygen-sensing mechanism that helps your body monitor and adapt to changes in oxygen levels and ensures that the cells receive an adequate supply of oxygen. The major component of this oxygen sensing system is Hypoxia Inducible Factors. These HIFs play an important role in responding to the body’s demand for more oxygen by activating genes and proteins for the development of new networks of blood vessels.

In the context of cancer, growing tumors can adapt to hypoxia by hijacking these HIFs for their survival. The HIFs can instigate the creation of new blood vessels to enhance oxygen supply. HIFs also alter how cancer cells metabolize glucose, enabling them to derive energy even in oxygen-deprived conditions.

Hypoxic cancer cells acquire additional capabilities, including metastasis (spreading beyond their origin) and resistance to chemotherapy and radiation treatments. The exact mechanisms by which hypoxic tumors acquire these harmful capabilities remain only partially understood. HIF activation is a contributing factor. Hypoxia in tumors also plays a significant role in their resistance to immunotherapy.

Furthermore, cancer cells adapt to hypoxic environments by using an alternative chemical pathway for energy production–one that does not rely on oxygen.