TPI1 and breast cancer: In addition, as demonstrated in human breast cancer Bcap37 cells, an acid pH may decrease glucose uptake and the glycolytic flux by directly inhibiting the activities of most glycolytic enzymes, including hexokinase (HK), aldolase, pyruvate kinase (PK), and LDH, with particular reference to phosphoglucose isomerase (PGI), phosphofructokinase (PFK), triosephosphate isomerase (TPI), and enolase, and through a mechanism that is independent of the presence of lactic acid [32].