GLS and breast cancer: MTF1, a transcription factor, maintains copper homeostasis and protects cells against injury caused by excess copper.[20] GLS plays a crucial role in the regulation of glutamine metabolism, and has been recognized as a novel biomarker and therapeutic target in cancers, such as breast cancer[21] and prostate cancer.[22] Furthermore, GLS is a CRG in renal cell carcinoma.[10] In our study, CDKN2A possessed the most frequent mutations.