Fibrosis and desmoplasia increase extracellular matrix (ECM) stiffness, which restricts diffusion of metabolites, protons, and other debris while directly reprogramming stromal cells toward glycolysis: a study in mammary models has shown that, even in the absence of tumour cells, normal stromal cells cultured on stiff ECM resembling tumour desmoplasia undergo glycolytic reprogramming, including upregulation of GLUT1 and MCT4 and increased lactate production113. This evidence concerns the gene SLC2A1 and neoplasm.