Since glutaminases (GLSs) are key enzymes allowing extracellular glutamine to be used for anaplerosis in cancer cells, with mitochondrial GLS particularly overexpressed in several types of cancer [3], GLS inhibitors, such as CB-839, are currently being tested in clinical trials (NCT02071862, NCT02071888, NCT02071927 and [96] NCT02861300) [97]. This evidence concerns the gene GLS and cancer.