Mice fed on a keto diet alongside an anti-diabetic drug were found to have slower progression rates of squamous cell carcinoma (SCC) lung tumours. The keto diet, currently widely popular, minimises sugar and carbohydrate intake.

SCC is a type of cancer formed by the squamous cells that make up the epithelial layer of organs, including the lung and oesophagus. There are currently few treatments available for this cancer type. However, previous research has indicated that SCC cells rely heavily on glucose for their growth, much more so than other cancer types, which researchers suspected could provide a promising therapeutic target.

In contrast to other types of cancer, SCC was found to upregulate the genes p63 and SOX2. These genes code for the membrane protein GLUT1 that facilitates the transport of glucose into the cell. The glucose can then be broken down to provide energy for the cell in a process known as glycolysis. As SCCs appear to be heavily dependent on glucose, researchers aimed to investigate if depriving cells of glucose could prevent tumour growth.

Mice were genetically engineered to develop a lung cancer that mimicked the human disease. The lung cancer consisted of both SCC and adenocarcinoma cells. The mice were fed a keto diet containing just 0.1% carbohydrates, which resulted in a reduced growth rate of the SCC cells. However, the diet did not affect the growth of adenocarcinoma cells and did not cause regression in either cancer.

The mice were then administered an anti-diabetic drug alongside the keto diet, which blocks glucose reabsorption into the kidneys. This further reduced SCC tumour growth. Next, the researchers knocked out the gene that codes for the GLUT1 transporter which reduced the size of the SCC tumours, indicating that the upregulation of GLUT1 plays a pivotal role in SCC tumourgenesis.

To investigate if these findings could be applied to humans, researchers measured the blood glucose level of patients with lung SCC, oesophageal SCC and lung adenocarcinoma. They then tracked the survival of the patients and observed a strong correlation between high blood glucose level and low survival rate in patients with either form of SCC.

These results represent a strong basis for developing a metabolic based cancer treatment for SCC.