PLACENTAL ALKALINE PHOSPHATASE (PLAP) is a membrane enzyme mainly expressed in the placenta. PLAP is shown to be expressed in ovarian cancer (OV), however, there is little known about its expression in other cancers. Using gene and protein expression deposited data, we surveyed PLAP expression across malignant and normal human tissues to explore the potential of PLAP as an immunotherapy target. We detected more than two-fold increased PLAP expression in multiple solid tumors including ovarian cancer, testicular germ cell tumors (TGCT), and uterine corpus endometrial carcinoma (UCEC) compared with matched normal tissues. We also showed association of PLAP expression with high mortality pancreatic adenocarcinoma (PAAD). Altogether, our results suggest that PLAP can be a promising target for immunotherapy of multiple cancers, especially OV, TGCT, and UCEC.

Introduction: This study was performed to establish a complementary method to the diagnosis of complete hydatidiform mole and its differentiation from the other cases of gestational trophoblastic disease by measuring the total (ALP) and PLACENTAL ALKALINE PHOSPHATASE (PLAP) specific activity. Materials and Methods: Serum and tissue extracts from 13 patients, 13 normal non-pregnant and 30 pregnant females were compared for these enzymes activities. Paranitrophenyl phosphate was used as substrate. PLACENTAL ALKALINE PHOSPHATASE was simply distingushed from its isoenzymes by its heat stability (65°c for 15min).Results: According to our findings from serum and tissue extract examination the activity of total ALKALINE PHOSPHATASE and PLACENTAL ALKALINE PHOSPHATASE activities were reduced in hydatidiform mole patients in comparsion with pregnant females (P<0.05) but there was no significant difference in non - pregnant subject. Conclusion: These results show a severe hypophosphatasia in serum and tissue extracts of the patients. The reduction in activity of enzymes may be caused by low synthesis of enzyme by trophoblast cells or some post transcriptional changes that causse the reduction of enzyme activity. Since the ALP is probably important in active transport of suger and phosphate across the trophoblast cell membreanes, so the hydropic villi of hydatidiform mole placenta may due to reduction of enzyme activity in PLACENTAL villi. Our results suggest that measurment of ALP and PLAP activity in serum and tissue extract can be a complementary method in diagnosis of hydatidiform mole.

Introduction: Production of Monoclonal antibody against ALKALINE PHOSPHATASE for application in immunohistochemical and immunocytochemical techniques such as ALKALINE PHOSPHATASE anti-ALKALINE PHOSPHATASE (APAAP) method.   Material and Methods: In this investigation female Balb/c mice were immunized by several injections of ALKALINE PHOSPHATASE and the antibody titer in their sera were measured after each injection. The spleen lymphocytes of immunized mice and Sp2/0 myeloma cells were fused using 50% polyethylen glycol as fusing agent and hybridoma cells were selected by HAT medium. Identification and selection of anti-ALKALINE PHOSPHATASE producing clones were done by performing ELISA test on supernatants of all the resulting clones. Limiting dilution was performed twice on antiboby producing clones for their seperation and the resulted subclones were propagated. Since APAAP complex must be enzymatically active for using in immunohistochemical techniques the adhesion of Ab molecule to enzyme molecule must not affect the enzyme activity. For investigation of this effect, an ELISA technique was planned and the supernatants of selected hybridoma clones were studied by this method. For production of concentrated Ab the hybridoma cells were injected to peritoneal cavity of mice and the ascetic fluids were obtained. Finally the antibodies isotypes were determined.   Results: After 6 fusion experiments 104 hybridoma clones were abtained and two clones (A1G9 and A1G8) which were antibody producing and had the highest absorbance in ELISA test were selected. Using the limiting dilution method finally two monoclonal subclones A1G8F7 and A1G9G3 were selected. ELISA experiments showed that antibodies which were produced by selected hybridoma clones did not react with active site of the enzyme and did not interfer with enzymatic activity. Electrophoresis of ascetic fluids of hybridoma injected mice showed a prominent band in γ position. Isotype determination of monoclonal antibodies showed that both hybridoma clones produce antibody from IgG class with k light chain.   Conclusion: Because monoclonal antibodies which are produced by the obtained hybridoma cell lines are from IgG class and do not affect the enzyme activity, it seem's that they are suitable for APAAP complex formation. Other steps of this study are now being performed until APAAP complex formation and it's application in immunohistochemistry.  

ALKALINE PHOSPHATASE (ALP; EC 3.1.3.1) is mainly derived from the liver, bones and in lesser amounts from intestines, placenta, kidneys and leukocytes. A raised level of ALKALINE PHOSPHATASE in the blood frequently indicates a variety of diseases. The examination of the ALP isoenzyme can be performed by electrophoresis. This examination can be helpful in disease classification of those cases with hyperALKALINEPHOSPHATASEmia. Of several ALP isoenzymes, biliary ALP isoenzyme is mentioned for its clinical usefulness in detection of biliary obstruction. Here, the authors performed a study to investigate the clinical usefulness of biliary ALKALINE PHOSPHATASE isoenzyme in biliary obstruction. Of interest, there is no significant difference of serum ALP level between malignant and benign biliary obstruction group. But there is a significant difference of serum biliary - ALP isoenzyme between malignant (range 28 U/L – 365 U/l) and benign biliary obstruction (range 20 – 140 U/L). Nevertheless, the average biliary - ALP level of the cholangiocarcinoma cases (range 105 – 365 U/L) is significant higher than the other malignant biliary obstruction cases (range 28 – 50 U/L). According to our study, the biliary - ALP isoenzyme determination can be use as a marker for malignant biliary obstruction.