Abstract
Alkaline phosphatase (ALP) is a group of enzymes that catalyze hydrolysis of phosphate esters at an alkaline pH, resulting in the generation of inorganic phosphate. These enzymes are widely distributed, and their activity is found in various tissues including bone, liver, intestine, and placenta. However, abnormalities in ALP expression and activity have been observed in certain types of cancer. In some cases, elevated serum levels of ALP are observed in patients with liver and bone metastasis. In other cases, increased levels of ALP have been observed in patients with pancreatic and lung cancer. On the other hand, low expression of ALP has also been associated with poor prognosis in patients with certain types of tumors, including colorectal cancer (CRC), breast cancer, and non-small cell lung cancer (NSCLC). In these cases, low ALP activity may be associated with decreased differentiation of cancer cells and increased cancer cell proliferation. Overall, the role of ALP in cancer is complex and context-dependent. This article reviews application progress of ALP in cancer, and we hypothesize that ALP might be a potential tumor biomarker, combined detection of aspartate aminotransferase (AST)/alanine aminotransferase (ALT), bone-specific alkaline phosphatase (BSAP), carbohydrate antigen 19-9 (CA 19-9), lactate dehydrogenase (LDH) and ALP isozymes levels can be used for more accurate diagnosis of a particular tumor. Further research is needed to better understand the mechanisms underlying ALP dysregulation in cancer and to identify potential therapeutic targets.