Gamma-glutamyl transferase expression in higher-grade astrocytic glioma.

Increased expression of gamma-glutamyltransferase (GGT) has been detected in a range of human malignancies and is thought to be involved in neoplastic proliferation and treatment resistance. Since GGT expression and its role in malignant glioma biology remain largely unknown, we investigated this phenomenon by immunostaining 26 higher-grade human astrocytic gliomas (WHO grades III and IV) with a monoclonal anti-GGT-antibody (138H11). Further, human pancreatic GGT cDNA was used for liposome-mediated transfection of 9L gliosarcoma cells. GGT-expressing and control 9L cells were cultured in media containing different amounts of essential amino acids and/or cytotoxic agents. Cell viability was evaluated by microplate MTT assay. Immunohistochemical staining of tumor specimens demonstrated that GGT expression is a frequent feature of higher-grade human astrocytic gliomas, but not of normal brain tissue. Human tumors were strongly GGT-positive in 6 of 7 cases of grade III astrocytoma, and in 12 of 19 grade IV astrocytoma (glioblastoma multiforme, GBM) cases. In the cell culture model, 9L-GGT cells had a growth advantage over control cells in cysteine-deficient medium. but not in standard or glutamine-free medium. No significant difference in numbers of viable cells of either clone was found in media containing the alkylating drug BCNU (5-200 microg/ml). In conclusion, GGT is expressed in a high percentage of human WHO grade III astrocytomas and GBM, but not in normal brain tissue. This molecule seems to give neoplastic cells a moderate growth advantage under in vivo conditions.

Effects on blood coagulation of adjuvant CNF (cyclophosphamide, novantrone, 5-fluorouracil) chemotherapy in stage II breast cancer patients.

We prospectively studied the alterations of coagulation during adjuvant CNF (Cyclophosphamide, Novantrone--Mitoxantrone, 5-Fluorouracil) chemotherapy in patients with stage II breast cancer. In 50 consecutive stage II breast cancer patients (pre-peri-postmenopausal), and 50 controls, serial coagulation parameters including prothrombin time (P.T.), partial thromboplastin time (P.T.T.), fibrinogen, fibrinogen/fibrin degradation products (F.D.P.), protein C, protein S, antithrombin III (AT-III) and platelet count were performed. Blood samples for coagulation tests were collected at pretherapy, midtherapy (before the 3rd course), before the 6th course of chemotherapy, and 2 months after the cessation of therapy (post-therapy) of 6 cycles of adjuvant chemotherapy (Cyclophosphamide 500 mg/m2, Novantrone 10 mg/m2, 5-Fluorouracil 500 mg/m2). Chemotherapy was repeated every 3 weeks. None of our stage II breast cancer patients receiving adjuvant CNF chemotherapy developed thromboembolic complications. Before any treatment all the tested coagulation parameters were within the normal limits as compared to controls. No statistically significant changes of FDP were noted throughout the study. Fibrinogen, plasma protein C, protein S and AT-III were significantly decreased during chemotherapy. This decline was more evident at midtherapy. Their levels returned to the pretherapy values 2 months after the completion of chemotherapy. The P.T. was statistically shortened, while the P.T.T. showed a statistically significant prolongation during chemotherapy. In conclusion, it appears that monitoring stage II breast cancer with sophisticated coagulation tests during adjuvant CNF chemotherapy can not identify patients at high risk for thromboembolic events. These serially performed coagulation tests, could be considered as a cost-intensive monitoring and not justifiable as a screening for breast cancer patients receiving adjuvant chemotherapy. However, the increasing number of reports of life-threatening and sometimes fatal thromboembolic events following chemotherapy or hormonochemotherapy are of great concern. Our results suggest caution when using chemotherapeutic agents in patients with other thrombosis risk factors, since a significant decrease of protein C and protein S was observed in all patients. Additional studies are required to determine the exact association between chemotherapy and/or hormonochemotherapy and thrombotic events.