GLS and cancer: Glutaminase (GLS) is an enzyme needed for the process of glutaminolysis which converts glutamine to glutamate.[13] Glutamine is an amino acid needed to support the growth of cancer cells and the formation of ATP.[14] In ovarian cancer with a high invasion rate, the rate of glutaminolysis will be higher than in ovarian cancer with a lower invasiveness.[15] This study assessed the use of preoperative serum CA-125, FASN, and GLS levels as predictors of cytoreduction in EOC, both individually and in combination.