[Expression of placental alkaline phosphatase in esophageal cancer cell line Eca109].

The expression and property of alkaline phosphatase (ALP) in Eca109 cells, a cell line derived from human esophageal carcinoma were studied with specific inhibition assay and poly-acrylamide gel electrophoresis. The results showed that ALP of Eca109 cells was heat stable and was strongly inhibited by L-phenyalanine, but slightly inhibited by urea. Prednisolone could cause dramatic increase in activity of ALP, but no change in ALP isozyme spectrum and concomitant increase in lactic dehydrogenase activity were found after prednisolone treatment. The results suggested that placental alkaline phosphatase as an oncofetal gene product could be expressed ectopically by Eca109 cells and prednisolone could specifically induce increase in its activity.