Cancer treatments often target cancer cells because the cells are rapidly growing and dividing. Like all growing cells, cancer cells need lots of building blocks and supplies. One of the major items used by cells is the amino acid glutamine. Glutamine can be used to help build many different cellular components. For this reason, blocking glutamine is an attractive target. New research shows that blocking glutamine can lead to great results in slowing and eliminating cancer in mouse models. The work also had a surprising result - blocking glutamine causes an increase in immune activity. This was not expected because immune cells also use glutamine to grow and reproduce. The result is very exciting and shows that attacking their supply line may be a great way to target cancer.