Phase II trial of zoledronic acid combined with androgen-deprivation therapy for treatment-naïve prostate cancer with bone metastasis.

BACKGROUND: The efficacy of zoledronic acid in patients with treatment-naïve prostate cancer is unclear. We conducted a phase II study to investigate the benefits of combined zoledronic acid and androgen deprivation therapy in treatment-naïve prostate cancer with bone metastasis. The primary endpoint was skeletal-related event-free survival at 24 months. METHODS: Subjects were treatment-naïve patients with histologically confirmed adenocarcinoma of the prostate and radiological evidence of bone metastasis. Treatment consisted of bicalutamide 80 mg daily, goserelin acetate 10.8 mg every 12 weeks, and zoledronic acid 4 mg every 4 weeks. Zoledronic acid was continued for 24 months. RESULTS: Of the patients enrolled between July 2008 and April 2010, 52 were included in the analyses. The median age of the patients was 72 years. The median baseline prostate-specific antigen level was 249.4 ng/mL. The median follow-up period was 33.3 months. The 24-month skeletal-related event-free survival rate was 84.4 % (95 % confidence interval 71.2-91.9). The median time to prostate-specific antigen progression was 25.9 months (95 % confidence interval 14.7-36.3). The median overall survival time was not reached. Improvement in pain or maintenance of no pain during the first 12 weeks was observed in 70 % of patients and the extent of bone disease was decreased in 10 % of patients at 12 months. Grade 3 osteonecrosis of the jaw was observed in three patients (5.8 %). CONCLUSION: Zoledronic acid concomitant with androgen deprivation therapy as initial treatment in patients with treatment-naïve prostate cancer with bone metastasis resulted in an encouraging skeletal-related event-free survival rate at 24 months.

Immunohistochemical detection of WT1 protein in a variety of cancer cells.

WT1 was first identified as a tumor suppressor involved in the development of Wilms' tumor. Recently, oncogenic properties of WT1 have been demonstrated in various hematological malignancies and solid tumors. Because WT1 has been identified as a molecular target for cancer immunotherapy, immunohistochemical detection of WT1 in tumor cells has become an essential part of routine practice. In the present study, the expression of WT1 was examined in 494 cases of human cancers, including tumors of the gastrointestinal and pancreatobiliary system, urinary tract, male and female genital organs, breast, lung, brain, skin, soft tissues and bone by immunohistochemistry using polyclonal (C-19) and monoclonal (6F-H2) antibodies against WT1 protein. Staining for C-19 and 6F-H2 was found in 35-100 and 5-88% of the cases of each kind of tumor, respectively. WT1-positive tumors included tumor of the stomach, prostate, and biliary and urinary systems, and malignant melanomas. A majority of the positive cases showed diffuse or granular staining in the cytoplasm, whereas ovarian tumors and desmoplastic small round cell tumors frequently showed nuclear staining. Glioblastomas, some of soft tissue sarcomas, osteosarcomas, and malignant melanomas of the skin showed extremely strong cytoplasmic staining as compared with other tumors. Western blot analysis showed that WT1 protein was predominantly expressed in the cytoplasm of the tumor cells in two cases of lung adenocarcinoma, supporting the intracytoplasmic staining for WT1 using immunohistochemistry. Immunohistochemical detection with routinely processed histologic sections could provide meaningful information on the expression of WT1 in cancer cells.