Alkaline phosphatase histochemistry and biochemistry in the diagnosis of complete hydatidiform mole.

The purpose of this study was a complementary method to the diagnosis and prognosis of complete hydatidiform mole (CHM) and differentiate it from the other cases of gestational trophoblatic diseases. This was done by examining the quality and quantity of the total and the placental alkaline phosphatase activity. The ALP in the tissues and sera from 12 patients were compared with 13 control normal non-pregnant and 30 control pregnant females. The enzyme activities were determined by biochemical and histochemical examination. The placental tissues were obtained from uterine curettage, or after delivery which then were frozen in a liquid nitrogen and processed for biochemical study. Cryosections were histochemically stained for ALP and PLAP by the azo coupling method. Isoenzyme specificity was evaluated by heating the tissue at 65 degrees C for 15 min while the including L-phenylalanine (50 mM), D-phenylalanine (50 mM) and L-homoarginine (50 mM) were used for chemical inhibition study. The activity of ALP and PLAP of patients were reduced in comparison with pregnant control group (P<0.05). There was no significant difference between the patients and non-pregnant control (P<0.05) group. The localization of enzyme activities in cryosections of all groups were in the basal, apical, and the cytoplasm of syncytiotrophoblast cells. The ALP in all the groups was thermostable (65 degrees C for 15 min) and was inhibited by L-phenylalanine, but no inhibition was seen with L homoarginine in patients group only. These findings suggest that the PLAP is a useful marker in the diagnosis and prognosis of hydatidiform mole.