Grouping the high-grade cartilage tumours (grade II and grade III chondrosarcomas) and the low-grade cartilage tumours (ACTs and enchondromas/osteochondromas) further demonstrated the significant difference in glutaminase expression levels between high-grade and low-grade cartilage tumours (p < 0.0001, independent-samples T test) (Fig. 2a). This evidence concerns the gene GLS and chondrosarcoma.