Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and 1.4% of cancer-related deaths (Reis and Faria, 1994). The prognosis of RCC remains poor. One third of the patients already have metastases when first consulting the hospital. Another 30-40% of patients develop metastases after surgical excision of the primary tumour (Ravaud and Debled, 1999). RCC are radioresistant (Nieder et al, 1996) and more than 80% are chemoresistant (Mickisch, 1994). Since RCC are presumed to be immunogenic, several clinical trials are exploring the efficacy of cytokines, mainly interleukin 2 (IL2) and/or interferon-α (IFNα), and the transfer of lymphokine-activated killer cells (Hofmockel et al, 1997;Bukowski, 2000;Hoffman et al, 2000). Despite these new options, the median survival time of patients with metastatic disease still remains only 6-8 months and the overall 5-year survival rate is less than 5% (Moch et al, 2000;Motzer and Russo, 2000). Thus, there is an urgent requirement for alternative therapeutic modalities.The current strategy is to design therapeutic approaches based on specific biological features of each tumour type. These include (i) the aberrant expression of genes which can be recognized by the immune system as foreign (Pawelec et al, 1999;Wang and Rosenberg, 1999;Bremers and Parmiani, 2000); (ii) gene products related to the formation of new blood vessels (neoangiogenesis), since they are essential for tumour expansion and metastatic settlement (Harris and Thorgeirsson, 1998;Kerbel, 2000;Rosen, 2000) and (iii) the altered expression of adhesion molecules, matrix-degrading enzymes, their receptors and inhibitors, which are a further requisite of metastatic spread (Huang et al, 1997;Yu et al, 1997).Several technique enable the identification of tumour markers. Subtractive hybridization (Lamar and Palmer, 1984; Kunkel et al, 1985;Kuang et al, 1998), differential display reverse transcription-polymerase chain reaction (DD RT-PCR; Liang and Pardee, 1992) and hybridization of cDNA microarrays (reviewed in Khan et al, 1999) are frequently used to compare the expression patterns between tumour and normal tissue. Other approaches, such as serological screening (SEREX;Sahin et al, 1995) and screening of cytotoxic T lymphocyte activity against an autologous tumour cell line (De Plaen et al, 1988), are especially focused on the identification of immunogenic tumour molecules.We have described recently the successful use of SSH using matched RCC and normal kidney tissue . In this study, we randomly selected 16 genes, which by SSH appeared to be differentially expressed. Differential expression of 9 of these 16 genes could be verified by Northern blot analysis. 2 of the 9 genes appeared to be novel. From the remaining 7 genes, expression of 5 had been associated with the malignant phenotype. To substantiate that SSH is a suitable method for the identification of differentially expressed genes, we performed a SSH with an additional pair of normal renal and RCC tissue and compared the validity of SSH ...

Localized prostate cancer (CaP) can be cured using several strategies. However, the need to identify active substances in advanced tumor stages is tremendous, as the outcome in such cases is still disappointing. One approach is to deliver human tumor antigen-targeted therapy, which is recognized by T cells or antibodies. We used data mining of the Cancer Immunome Database (CID), which comprises potential immunologic targets identified by serological screening of expression libraries. Candidate antigens were screened by DNA microarrays. Genes were then validated at the protein level by tissue microarrays, representing various stages of CaP disease. Of 43 targets identified by CID, 10 showed an overexpression on the complementary DNA array in CaP metastases. The RHAMM (CD168) gene, earlier identified by our group as an immunogenic antigen in acute and chronic leukemia, also showed highly significant overexpression in CaP metastases compared with localized disease and benign prostatic hyperplasia. At the protein level, RHAMM was highest in metastatic tissue samples and significantly higher in neoplastic localized disease compared with benign tissue. High RHAMM expression was associated with clinical parameters known to be linked to better clinical outcome. Patients with high RHAMM expression in the primaries had a significantly lower risk of biochemical failure. The number of viable cells in cell cultures was reduced in blocking experiments using hormone-sensitive and hormone-insensitive metastatic CaP cell lines. Acknowledging the proven immunogenic effects of RHAMM in leukemia, this antigen is intriguing as a therapeutic target in far-advanced CaP.

OBJECTIVE To evaluate [11C]‐choline positron‐emission tomography (PET)/computed tomography (CT) for detecting clinical recurrence after primary treatment for prostate cancer. PATIENTS AND METHODS In all, 50 patients with prostate cancer who had had initial therapy (radical prostatectomy in 40, external beam radiation in three and interstitial brachytherapy in seven) had PET/CT using [11C]‐choline in the presence of an increased or increasing prostate‐specific antigen (PSA) level. The mean (range) time to biochemical progression was 22 (2–136) months. Current PSA levels were determined in all patients at the time of examination. The results were correlated with the histopathology reports after targeted biopsy or surgery, and with the clinical follow‐up. RESULTS The mean (median, range) PSA level in patients with positive PET/CT was 3.62 (2.42, 0.5–13.1) ng/mL, and that in patients with a negative scan was 0.90 (0.95, 0.41–1.40) ng/mL. PET/CT was positive in seven of 13 patients with a PSA level of <1.5 ng/mL, and histology was positive in this group in nine. In 17 patients with PSA levels of 1.5–2.5 ng/mL PET/CT was positive in all and the histology was positive in 13; in 11 men with a PSA level of 2.5–5 ng/mL PET/CT was positive in all 11 and the histology was positive in 10; in nine men with PSA levels of >5 ng/mL PET/CT identified all as positive and the histology was positive in eight. The sensitivity at a PSA level of <2.5 ng/mL of PET/CT for detecting recurrence was 91% (95% confidence interval, 71–99%) with a specificity of 50% (16–84)%. CONCLUSION [11C]‐choline PET/CT seems to be useful for re‐staging prostate cancer after curative therapy and with increasing PSA levels; this was verified by histological examination. We recommend this method at PSA levels of <2.5 ng/mL.

The glycogen synthase kinase 3 (GSK-3) is a serine/threonine kinase widely expressed in mammalian tissues. Initially identified by its ability to modulate glycogen synthesis, GSK-3 turned out to be a multifunctional enzyme, able to phosphorylate many proteins, including members of the steroid receptor superfamily. Although GSK-3 was shown to phosphorylate the androgen receptor (AR), its effects on AR transcriptional activity remain controversial. Analysis of short hairpin RNA (shRNA)-mediated downmodulation of GSK-3 proteins in prostate cancer cells showed a reduction in AR transcriptional activity and AR protein levels. Pharmacological GSK-3 inhibitors such as the maleimide SB216763 or the aminopyrazole GSK inhibitor XIII inhibited AR-dependent reporter gene activity and AR expression in vitro. Analysis of androgen-induced nuclear translocation of the AR was performed in PC3 cells transfected with pAR-t1EosFP coding for EosAR, a green fluorescent AR fusion protein. When grown in presence of androgens, EosAR was predominantly nuclear. Incubation with SB216763 before and after androgen treatment almost completely reduced nuclear EosAR. In contrast, the thiazole-containing urea compound AR-A014418 increased rather than decreased AR-expression/function. Although not all GSK inhibitors affected AR-stability/function, our observations suggest a potential new therapeutic application for some of these compounds in prostate cancer.

Chronic inflammation increases the risk of cancer and many cancers, including prostate cancer, arise at sites of chronic inflammation. Inducible nitric oxide synthase (iNOS) is an enzyme dominantly expressed during inflammatory reactions. Although synthesis of high amounts of nitric oxide (NO) by iNOS has been demonstrated in pathophysiological processes, such as acute or chronic inflammation, autoimmune diseases or tumorigenesis, the role of iNOS activity in most of these diseases is poorly understood. Analysing prostate cancer biopsies by immunohistochemistry we found iNOS protein expression in tumor cells strongly paralleled by nitrotyrosine suggesting that iNOS is fully active. In vitro, NO inhibits androgen receptor-dependent promoter activity and prostate specific antigen production as well as DNAbinding activity of the androgen receptor (AR) in a concentration-dependent manner. Inhibition of the activity of androgen receptor-dependent reporter constructs is neither owing to diminished AR protein levels nor owing to an inhibition of its nuclear import. In addition, NO inhibits the proliferation of androgen receptor-positive prostate cancer cells significantly more efficiently than proliferation of androgen receptor-negative prostate cancer cells. In summary, our findings suggest that intratumoral iNOS activity favors development of prostate cancer cells that are able to proliferate androgen receptor-independently, thereby promoting prostate tumor progression.