A.J. Schrader

Detecting predictive androgen receptor modifications in circulating prostate cancer cells

Molecular modifications of the androgen receptor (AR) can cause resistance to androgen deprivation therapy (ADT) in prostate cancer patients. Since lack of representative tumor samples hinders therapy adjustments according to emerging AR-modifications, we evaluated simultaneous detection of the two most common AR modifications (AR-V7 splice variant and AR point mutations) in circulating tumor cells (CTCs). We devised a single-tube assay to detect AR-V7 splice variants and AR point mutations in CTCs using immunomagnetic cell isolation, followed by quantitative real-time PCR and DNA pyrosequencing. We prospectively investigated 47 patients with PSA progression awaiting therapy switch. Comparison of response to newly administered therapy and CTC-AR-status allowed effect size estimation. Nineteen (51%) of 37 patients with detectable CTCs carried AR-modifications. Seventeen patients carried the AR-V7 splice variant, one harbored a p.T878A point mutation and one harbored both AR-V7 and a p.H875Y mutation. We estimated a positive predictive value for response and non-response to therapy by AR status in CTCs of ~94%. Based on a conservative calculation, we estimated the effect size for molecularly-informed therapy switches for prospective clinical trial planning to ~27%. In summary, the ability to determine key resistance-mediating AR modifications in CTCs has the potential to considerably improve prostate cancer treatment.

Validation of CRP as prognostic marker for renal cell carcinoma in a large series of patients

BackgroundTo evaluate the prognostic significance of the pre-operative C-reactive protein (CRP) serum level in patients with renal cell cancer (RCC).MethodsWe evaluated 1,161 RCC patients with complete patient and tumour specific characteristics as well as information about their pre-operative CRP-level, who had undergone either radical nephrectomy or nephron-sparing surgery at two German high-volume centres (University Hospitals of Hannover and Ulm). The mean follow-up was 54 months.ResultsThe CRP-level, stratified to three subgroups (CRP ≤ 4, 4–10, and >10 mg/l), correlated significantly with tumour stage (p < 0.001), the risk of presenting nodal disease (2.1, 3.1, and 16.4%) and distant metastasis (2.9, 8.6, and 30.0%; p < 0.001). The Kaplan-Meier 5-year cancer specific survival (CSS) rates were 89.4, 77.9, and 49.5%, respectively (p < 0.001). Multivariate analysis identified CRP as an independent prognosticator for CSS as well as overall survival (p < 0.001). Patients with a CRP of 4–10 and >10 mg/l had a 1.67 and 2.48 fold higher risk of dying due to their RCC compared to those with a pre-operative CRP ≤4 mg/l, respectively.ConclusionsA high preoperative serum CRP level is an independent predictor of poor survival in patients with RCC. Its routine use could allow better risk stratification and risk-adjusted follow-up of RCC patients.

Expression of AR-V7 in Circulating Tumour Cells Does Not Preclude Response to Next Generation Androgen Deprivation Therapy in Patients with Castration Resistant Prostate Cancer

The androgen receptor splice variant AR-V7 has recently been discussed as a predictive biomarker for nonresponse to next-generation androgen deprivation therapy (ADT) in patients with castration-resistant prostate cancer. However, we recently identified one patient showing a response from abiraterone despite expression of AR-V7 in his circulating tumour cells (CTC). Therefore, we precisely assessed the response in a cohort of 21 AR-V7 positive castration-resistant prostate cancer patients who had received therapy with abiraterone or enzalutamide. We detected a subgroup of six AR-V7 positive patients showing benefit from either abiraterone or enzalutamide. Their progression free survival was 26 d (censored) to 188 d. Four patients displayed a prostate-specific antigen decrease of >50%. When analysing prior therapies, we noticed that only one of the six patients had received next-generation ADT prior to CTC collection. As a result, we conclude that AR-V7 status in CTC cannot entirely predict nonresponse to next generation ADT and AR-V7-positive patients should not be systematically denied abiraterone or enzalutamide treatment, especially as effective alternative treatment options are still limited. PATIENT SUMMARY A subgroup of patients can benefit from abiraterone and/or enzalutamide despite detection of AR-V7 splice variants in their circulating tumour cells.

Metastatic non-clear cell renal cell carcinoma: current therapeutic options.

Non‐clear cell (ncc) renal cell carcinoma (RCC) accounts for ≈25% of all patients with metastatic RCC. It is refractory to standard immuno(chemo)therapy and, to date, no specific trials have been reported to evaluate the efficacy of novel targeted drugs in the different subtypes of metastatic nccRCC. We review all available data from subgroup analyses of the global sorafenib and sunitinib expanded access programmes, current phase‐III trials, and smaller multi‐ and single‐centre studies focusing on the activity of targeted agents in these specific and rare RCC subtypes. Both sorafenib and sunitinib have significant activity in metastatic nccRCC, but the efficacy of each agent seems to vary between different nccRCC forms. Preliminary clinical data for temsirolimus appear to be promising but more extensive and long‐term data are awaited. With the advent of novel therapeutic options, specific controlled multicentre trials are urgently needed to define their exact value and efficacy for treating the historically resistant nccRCC forms. The medium‐term aim should be to tailor the most advantageous therapy for each patient with respect to his/her individual RCC subtype and physical condition.

Biochemical markers of bone turnover in patients with localized and metastasized prostate cancer.

To evaluate and compare the value of several markers of bone turnover in different stages of prostate cancer, as bone metastases are a common feature in this disease, and for assessing bone metastases both bone formation and bone resorption markers are diagnostic.

Second-line strategies for metastatic renal cell carcinoma: classics and novel approaches

Objectives: Renal cell carcinoma is an aggressive malignancy with a high propensity for both early and metachronous regional and distant metastasis. While surgical resection is the mainstay of therapy for patients with localized disease, the prognosis for patients with distant metastasis is poor with a 5-year survival rate of less than 10%. Response rates to first-line immunotherapy or immunochemotherapy range from 10–35%; responses achieved are predominantly partial remissions of short duration. Until today, there is no standard therapeutic procedure for the growing number of patients who relapse following first-line therapy and desire further active treatment. Materials and Methods: This article reviews classic and recent publications about second- and third-line approaches, their potential efficacy and toxicity. Results: Several novel approaches have raised well-founded hope. Especially the application of monoclonal antibodies targeting VEGF signalling as well as different receptor tyrosine kinase inhibitors have the potential to change the face of second-line treatment of patients with metastatic RCC. Both groups of agents are focused in current phase III trials, either as mono- and/or combination therapy. Conclusions: Until today, second-line treatment of patients with metastatic RCC progressing under therapy with biological response modifiers remains an unresolved issue. The results of ongoing clinical trials evaluating novel targeted approaches can be expected with suspense.

Tumor markers in peripheral blood of patients with malignant melanoma: multimarker RT-PCR versus a luminoimmunometric assay for S-100.

Abstract The identification of circulating tumor cells in the peripheral blood of patients with malignant melanoma by detection of melanoma associated protein transcripts using the reverse transcriptase polymerase chain reaction (RT-PCR) technique has been introduced as a noninvasive and sensitive technique for early detection of tumor progression and metastatic disease. An alternative approach is the analysis of S-100 protein in the serum of melanoma patients by a luminoimmunometric assay (LIA). In this study, the sensitivities of RT-PCR and LIA were compared. Seventy-seven blood samples of 59 melanoma patients were analyzed for tyrosinase, Melan-A/MART-1, MAGE-3, gpl00, and p97 expression by multimarker RT-PCR; 540 serum samples of 352 melanoma patients were analyzed for S-100 protein concentration by LIA. In stage III 23.8% and in stage IV 37.5% of the samples were positive for at least one marker in multimarker RT-PCR, versus 8.1% and 48.1% of elevated S-100 levels analyzed by LIA, respectively. In a direct comparison, 31 identical samples were analyzed by multimarker RT-PCR and by S-100 LIA. In stage III 18.2% and in stage IV 45% of the samples were positive by multimarker RT-PCR versus 45.5% and 80% by S-100 LIA, respectively. S-100 LIA was more sensitive in detection of metastatic disease in melanoma patients than multimarker RT-PCR and should be evaluated in further studies. RT-PCR might be more useful in the analysis of micrometastases in anatomic compartments other than peripheral blood.

Adaptive responses of androgen receptor signaling in castration-resistant prostate cancer

Prostate Cancer (PCa) is an important age-related disease being the most common cancer malignancy and the second leading cause of cancer mortality in men in Western countries. Initially, PCa progression is androgen receptor (AR)- and androgen-dependent. Eventually advanced PCa reaches the stage of Castration-Resistant Prostate Cancer (CRPC), but remains dependent on AR, which indicates the importance of AR activity also for CRPC. Here, we discuss various pathways that influence the AR activity in CRPC, which indicates an adaptation of the AR signaling in PCa to overcome the treatment of PCa. The adaptation pathways include interferences of the normal regulation of the AR protein level, the expression of AR variants, the crosstalk of the AR with cytokine tyrosine kinases, the Src-Akt-, the MAPK-signaling pathways and AR corepressors. Furthermore, we summarize the current treatment options with regard to the underlying molecular basis of the common adaptation processes of AR signaling that may arise after the treatment with AR antagonists, androgen deprivation therapy (ADT) as well as for CRPC, and point towards novel therapeutic strategies. The understanding of individualized adaptation processes in PCa will lead to individualized treatment options in the future.

[Gender-specific characteristics and survival of renal cell carcinoma].

BACKGROUND Renal cell carcinoma (RCC) occurs twice as often in men as in women; however, the influence of gender on stage, grade, subtype and prognosis has not been studied in detail. METHODS This study included 780 patients treated by (partial) nephrectomy at our institution in Marburg between 1990 and 2005. The mean follow-up was 5.44 years. RESULTS Of the 780 patients, 486 (62%) were men and 294 (38%) were women. Women were significantly older (mean, 65.3 vs. 62.2 years; p<0.001, t-test), presented at lower T stages (p=0.046, chi(2)) and suffered metastasis less frequently at diagnosis (p=0.026, chi(2)). In addition, women more frequently had clear cell tumours (85.2% vs. 78.3%) and less frequently papillary tumours (11.0% vs. 18.8%) than men (p=0.026, chi(2)). In contrast, men had an increased risk of death from RCC (HR 1.23, CI 0.92-1.63); Kaplan-Meier curves revealed a significant difference in tumour-specific survival between men and women (p=0.033, log rank; 5-year survival 74% vs. 83%). However, unlike tumour stage and tumour grade, gender could not be retained as a significant independent prognostic marker in multivariate analysis. CONCLUSION In general, RCC in men is characterized by higher tumour stages and more frequent metastasis at diagnosis along with inferior tumour-specific survival. However, as gender failed to qualify as an independent prognostic marker for tumour-specific survival, delayed diagnosis due to insufficient routine medical check-up and/or a more aggressive tumour biology might be be a concurrent cause. Thorough regular medical check-ups for men, also with regard to RCC, are thus mandatory.

Preoperative serum C- reactive protein: a prognostic marker in patients with upper urinary tract urothelial carcinoma

BackgroundTo analyse the prognostic significance of preoperative C-reactive protein (CRP) serum level in patients with upper urinary tract urothelial carcinoma (UUT-UC).MethodsWe evaluated 158 UUT-UC patients who had undergone surgery in the University Hospital of Hannover (MHH). 143 (89.4%) suffered from cancer in the renal pelvis, 13 (8.1%) patients presented with tumour located in the ureter. A preoperative CRP value was available for 115 patients. The mean (median) follow-up for these patients was 28.3 (15.1) months.ResultsThe median (mean) CRP value of all evaluable patients was 10.0 (40.7) mg/l. The CRP-level, stratified into two subgroups (CRP ≤5 vs. >5 mg/l), correlated significantly with muscle invasive tumour stage (36.4 vs. 78.9%; p<0.001), the risk of presenting nodal disease (4.5 vs. 26.8%; p=0.002) and distant metastasis (2.3 vs. 16.9%; p<0.016). The Kaplan-Meier 5-year cancer specific survival (CSS) rates were 54.2 and 26.4% for patients with preoperative CRP levels ≤ and >5 mg/l, respectively (p<0.006). Next to age and the presence of metastasis, multivariate analysis also identified CRP as a continuous variable as an independent prognosticator for CSS.ConclusionsA high preoperative serum CRP level is associated with locally advanced and metastatic disease in patients with UUT-UC. Its routine use could allow better risk stratification and risk-adjusted follow-up of UUT-UC patients.