More recently, based on global metabolite profiling of tumors as well as numerous human breast cancer cell lines including MCF7 and MDA-MB231, glutaminase overexpression was shown to elevate the levels of 2-hydroxyglutarate, which potentially serves as an oncometabolite biomarker for some types of breast cancer (Terunuma et al., 2014). This evidence concerns the gene GLS and breast cancer.