MKI67 and neoplasm: In addition to the marked difference in tumour volumes, cross-sections of PDX tumours from mice fed with glutamine-supplemented diet appeared to have more necrotic or apoptotic regions by haematoxylin and eosin (H&E) staining (Fig. 3g) accompanied by decreased proliferation by Ki67 staining compared to control (Fig. 3h and Supplementary Fig. 2e).