Causes and consequences of tumour acidity and implications for treatment

Abstract

Tumour cells have a lower extracellular pH (pH e) than normal cells; this is an intrinsic feature of the tumour phenotype, caused by alterations either in acid export from the tumour cells or in clearance of extracellular acid. Low pH e benefits tumour cells because it promotes invasiveness, whereas a high intracellular pH (pH i) gives them a competitive advantage over normal cells for growth. Molecular genetic approaches have revealed hypoxia-induced coordinated upregulation of glycolysis, a potentially important mechanism for establishing the metabolic phenotype of tumours. Understanding tumour acidity opens up new opportunities for therapy.