P.F.A. Mulders

Molecular cloning and immunogenicity of renal cell carcinoma-associated antigen G250

The molecular cloning of the cDNA and gene encoding the renal cell carcinoma (RCC)‐associated protein G250 is described. This protein is one of the best markers for clear cell RCC: all clear‐cell RCC express this protein, whereas no expression can be detected in normal kidney and most other normal tissue. Antibody studies have indicated that this molecule might serve as a therapeutic target. In view of the induction/up‐regulation of G250 antigen in RCC, its restricted tissue expression and its possible role in therapy, we set out to molecularly define the G250 antigen, which we identified as a transmembrane protein identical to the tumor‐associated antigen MN/CAIX. We determined, by FISH analysis, that the G250/MN/CAIX gene is located on chromosome 9p12‐13. In view of the relative immunogenicity of RCC, we investigated whether the G250 antigen can be recognized by TIL derived from RCC patients. The initial characterization of 18 different TIL cultures suggests that anti‐G250 reactivity is rare. Int. J. Cancer 85:865–870, 2000.

Preliminary analysis of patients with progressive renal cell carcinoma vaccinated with CA9-peptide-pulsed mature dendritic cells.

Carbonic anhydrase-IXG250/MN (CA9) is a renal cell carcinoma (RCC)-associated antigen ubiquitously expressed in the clear-cell subtype of RCC. Two CA9-derived peptides have been identified defining a cytotoxic T-lymphocyte epitope and human leukocyte antigen (HLA)-DR epitope, able to induce T-cell responses in vitro. A phase I clinical trial was performed with CA9-peptide–loaded dendritic cells (DCs) in patients with progressive, cytokine-refractory metastatic RCC to assess the safety, toxicity, and induction of CA9-specific immunity. Patients with objective progressive metastatic RCC received 5 vaccinations of mature DCs pulsed with the CA9-derived peptides and keyhole limpet hemocyanine (KLH). Peripheral blood was collected at regular intervals, delayed-type hypersensitivity (DTH) was tested at baseline and after the last vaccination, and skin biopsies of positive DTH sites were collected for immunomonitoring purposes. Patients were also monitored for clinical responses. No significant toxicity was observed. All patients developed humoral responses against KLH, and demonstrated DTH conversion. Evaluation of biopsy material suggested an increased influx of T-helper cells. In none of the immunomonitoring assays was evidence for the induction of CA9-peptide–specific immunity observed. No clinical responses were observed. The vaccination of DCs pulsed with KLH and 2 CA9-derived peptides was well tolerated. The lack of induction of CA9-peptide–specific immune responses indicates that this particular vaccine regimen is poor in inducing CA9-peptide–specific immune responses.

Functional MRI techniques demonstrate early vascular changes in renal cell cancer patients treated with sunitinib: a pilot study

Abstract Objective: To assess the early vascular effects of sunitinib in patients with renal cell carcinoma (RCC) with diffusion-weighted magnetic resonance imaging (DWI), dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and T2* perfusion MRI. Patients and methods: In 10 patients with abdominal RCC lesions, DWI, DCE-MRI and T2* perfusion MRI measurements at 3 Tesla were performed at baseline, 3 and 10 days after start of sunitinib. VEGF-A plasma levels were measured on days 0, 3 and 10. Results: DWI showed a significant increase in the apparent diffusion coefficient (×10−6 s/mm2) from baseline (mean 1158, range 814–2003) to day 3 (mean 1306, range 1008–2097, P = 0.015) followed by a decrease to baseline levels at day 10 (mean 1132, range 719–2005, P = 0.001). No significant changes were found in mean DCE-MRI parameters. T2* perfusion MRI showed a significant decrease in relative tumor blood volume (rBV) and relative tumor blood flow (rBF) at day 3 (rBV P = 0.037, rBF P = 0.018) and day 10 (rBV P = 0.006, rBF P = 0.009). VEGF-A plasma levels significantly increased after 10 days, but did not correlate with MRI parameters. Conclusions: Sunitinib induces antiangiogenic effects as measured by DWI and T2*-perfusion MRI, 3 and 10 days after the start of the initial treatment. DCE-MRI did not show significant changes. In the near future, early functional MRI-based evaluation can play an important role in tailoring treatment to the individual patient with RCC. Further investigation is warranted.

111In-Bevacizumab Imaging of Renal Cell Cancer and Evaluation of Neoadjuvant Treatment with the Vascular Endothelial Growth Factor Receptor Inhibitor Sorafenib

Clear cell renal cell cancer (ccRCC) prominently expresses vascular endothelial growth factor-A (VEGF-A), and new treatment strategies for renal cell cancer (RCC) aim at the inhibition of VEGF–VEGF receptor signaling. This study explores the ability of 111In-bevacizumab scintigraphy to depict RCC and to evaluate response to neoadjuvant treatment with sorafenib, a VEGF receptor inhibitor. Methods: The ability to depict RCC with 111In-bevacizumab scintigraphy was tested in 14 patients scheduled to undergo a tumor nephrectomy; of these, 9 RCC patients were treated in a neoadjuvant setting with sorafenib (400 mg orally twice a day). In the latter group, baseline and posttreatment 111In-bevacizumab scans were compared. The intratumoral distribution of 111In-bevacizumab was determined scintigraphically ex vivo in a 1-cm lamella of the resected tumorous kidney. Expression of VEGF-A, glucose transporter-1, carbonic anhydrase IX, α-smooth-muscle actin, and Ki67 was determined by immunohistochemistry and compared with the local concentration of 111In-bevacizumab. Additionally, the VEGF-A content in tumor samples was determined quantitatively by enzyme-linked immunosorbent assay. Results: In all 5 non–neoadjuvant-treated patients, preferential accumulation of 111In-bevacizumab was observed in the tumors. All ccRCC lesions with enhanced 111In-bevacizumab targeting expressed high levels of VEGF-A. Treatment with sorafenib resulted in a significant decrease of 111In-bevacizumab uptake in the tumor in the patients with ccRCC (mean change, −60.5%; range, +1.5% to −90.1%). The decrease in uptake was due to destruction of the tumor neovasculature, whereas the VEGF-A expression remained intact. In the patient with papillary RCC, limited uptake without change after sorafenib was observed. Conclusion: RCC lesions were clearly delineated with 111In-bevacizumab scintigraphy. Neoadjuvant treatment with sorafenib resulted in a significant decrease of 111In-bevacizumab uptake in RCC. 111In-bevacizumab scintigraphy can be an attractive biomarker for response and needs further study.

Tyrosine Kinase Inhibitor Sorafenib Decreases 111In-Girentuximab Uptake in Patients with Clear Cell Renal Cell Carcinoma

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of metastatic clear cell renal cell carcinoma (RCC). Although TKIs have demonstrated good clinical efficacy, the lack of complete responses, the chronic nature of the treatment, and the side effects are clear disadvantages. An interesting new approach in the treatment of clear cell RCC is antibody-mediated therapy with the chimeric anti–carbonic anhydrase IX (CAIX) antibody girentuximab (cG250). As the results of several girentuximab trials become available, the question arises of whether TKI treatment can be combined with girentuximab-based therapy. In this study, we assessed the effect of the widely used TKI sorafenib on the tumor-targeting potential of 111In-labeled girentuximab. Methods: 111In-girentuximab imaging was performed on 15 patients suspected of having a renal malignancy, with surgery being part of their treatment plan. Of these, 10 patients were treated in a neoadjuvant setting with sorafenib (400 mg orally twice daily). Five patients received treatment during 1 wk, and 5 patients received treatment during 4 wk. In both sorafenib-treated groups, baseline and posttreatment tumor targeting of 111In-girentuximab were compared. Surgery was performed 3 d after the last image acquisition. Five additional patients were included as a control group and had only a single 111In-girentuximab injection and scintigraphy without any treatment. Distribution of 111In-girentuximab was determined scintigraphically ex vivo in a 1-cm lamella of the resected tumorous kidney. Expression of CAIX and of the vascular marker CD31 was determined immunohistochemically on specimens of both tumor and normal kidney tissue. Results: Treatment with sorafenib resulted in a marked decrease of 111In-girentuximab uptake in the tumor in clear cell RCC patients, especially in the group treated for 4 wk (mean change in both sorafenib-treated groups, −38.4%; range, +9.1% to −79.4%). Immunohistochemical analysis showed markedly reduced CD31 expression and vessel density in the sorafenib-treated groups but no differences in CAIX expression between the sorafenib-treated groups and the nontreated patients. Conclusion: Treatment with sorafenib resulted in a treatment duration–dependent significantly decreased uptake of 111In-girentumab in clear cell RCC lesions. These results indicate that the efficacy of antibody-mediated treatment or diagnosis modalities is hampered by TKI treatment.

18 Een directe vergelijking van prostaatkankerbiomarkers in drie urinefracties: onbewerkte urine, sediment en exosomen

SamenvattingHet prostaatspecifiek antigeen (PSA) wordt gebruikt als tumormarker voor prostaatkanker, maar heeft als belangrijk nadeel dat het niet specifiek is. PCA3 en TMPRSS2-ERG zijn prostaatkankerspecifieke biomarkers die gedetecteerd kunnen worden in urine. Urine is een complex substraat en bestaat uit meerdere fracties.

1 Dual-modality imaging bij niercelcarcinoom. Een ex-vivonierperfusiestudie

SamenvattingBeeldgestuurde chirurgie kan van meerwaarde zijn om complete tumorresectie te bereiken. Hiervoor kunnen radioactieve en/of fluorescerende antitumorantilichamen gebruikt worden.

43 PCA3- en TMPRSS2-ERG-expressie en respons in castratieresistente prostaatkankerpatiënten behandeld met docetaxel

Resultaten PCA3en TMPRSS2-ERG mRNA-expressie werd gevonden bij respectievelijk 5 (50%) en 4 (40%) patiënten. Al deze patiënten lieten een positieve biomarkerexpressie zien bij de baselinemeting en een afname tijdens behandeling. Na het beëindigen van de behandeling werd er een lichte stijging in PCA3en TMPRSS2-ERG-expressie waargenomen ten opzichte van de waarden gedurende de behandeling. Voor beide markers werd geen duidelijke correlatie gezien met gemiddelde serum PSA-waarden.

Indium-111-cG250 immunoSPECT als diagnostisch hulpmiddel bij het management van incidentalomen van de nier

Introductie Tumorcellen van het heldercellig niercelcarcinoom (clear cell renal cell carcinoma: ccRCC) brengen in meer dan 85% van de gevallen het antigeen carbonic anhydrase IX (CAIX) tot expressie. Dit antigeen wordt niet tot expressie gebracht in normale niercellen of niercysten. De hoge en specifieke expressie van dit antigeen maakt het mogelijk om ccRCC-laesies preoperatief in beeld te brengen middels radioactief gelabelde anti-CAIX-antilichamen, wat zeer nuttig kan zijn voor de klinische besluitvorming en chirurgische behandeling van patiënten die zich presenteren met een incidentaloom.