Interstitial loss and gain of sequences on chromosome 22 in meningiomas with normal karyotype

In nearly half of sporadic low grade meningiomas no chromosome aberration can be detected. In the majority of the other half chromosome 22 is lost. In higher grade meningiomas this loss is followed by characteristic secondary chromosome aberrations. Regarding the molecular findings in Schwannomas, homozygous loss or mutation of the NF2 gene located on chromosome 22, was supposed also to be the primary event in meningioma development. However, in nearly all high grade but in only a minority of low grade meningiomas the loss of the NF2 protein is observed. Therefore, both the hypothetical combined heterozygous loss of or inactivation of two or more tumour suppressor genes (at least one of them located on chromosome 22) or the homozygous loss of a regulatory gene on chromosome 22 different from NF2 was discussed. In search for microdeletions or/and structural recombinations of chromosome 22 we investigated primary cell cultures of 43 meningiomas by conventional G-banding (26 without, 17 with loss of chromosome 22). Twenty-seven tumours were analysed with spectral karyotyping (SKY) and 16 with fluorescence in situ hybridisation (FISH) with DNA probes for the chromosomal regions of 22q11.2, 22q11.23q12.1, 22q12.1 and 22q13.3. SKY analysis confirmed G-banding data for chromosome 22 and could specify marker chromosomes and translocations containing material from chromosome(s) 22. Confirming our assumption microdeletions on chromosome 22 were detected by FISH in 6/8 cytogenetically non-aberrant meningiomas. Surprisingly, in 2/8 cases we observed gains of the 22q13.3 and in 2/8 gains of the 22q12.1 region. Here we present first evidence for an uncommon mechanism during early meningioma development at least for a meningioma subgroup: i) duplication and translocation of sequences from chromosome 22 to different chromosomes. ii) deletion of the original sequences on chromosome 22, resulting in disomy again (only visible as translocation in metaphase FISH). iii) loss of chromosome 22.     

Cytokine and vaccine therapy of kidney cancer

In this paper, results from current randomized and other relevant studies on cytokine and vaccine therapy of kidney cancer in the adjuvant setting and in metastatic disease are reviewed. Improvement of medical therapy of kidney cancer is required since the relative 5-year survival of kidney cancer is only 62%. In the adjuvant setting, cytokine monotherapy (interferon [IFN]-alpha or interleukin [IL]-2) is not effective in improving progression-free or overall survival. Recently, an autologous kidney cancer cell vaccine has been shown to reduce the risk of tumor progression following radical nephrectomy for organ-confined or locally advanced kidney cancer in a randomized Phase III study. There were only a few vaccine-related side effects. Presently, this is the only promising approach for the adjuvant treatment of kidney cancer following nephrectomy. In metastatic kidney cancer patients with the tumor-bearing kidney in situ, a combination of radical nephrectomy plus IFN-alpha is more effective than IFN-alpha alone. In metastatic kidney cancer without the option of operative removal of the primary tumor and/or metastases, cytokines such as IFN-alpha, IL-2 and IL-12 and their combinations result in response rates of 10-30%, but the 5-year overall survival is less than 10%. Furthermore, the ideal dose, administration and combination of different agents are yet to be defined. Vaccine therapy of metastatic kidney cancer has been investigated only in Phase I and II studies with limited clinical benefit. Based on the current literature there is a clear need for new approaches in metastatic kidney cancer.     

High-throughput genotyping by DHPLC of the dihydropyrimidine dehydrogenase gene implicated in (fluoro)pyrimidine catabolism

Dihydropyrimidine dehydrogenase (DPD) is the first and rate-limiting enzyme in the degradation of pyrimidines and pyrimidine base analogs including the anticancer drugs 5-fluorouracil (5-FU) and Xeloda. A decreased DPD enzyme activity has been described in cancer patients experiencing severe and life-threatening toxicity after 5-FU treatment and distinct sequence variants in the DPD gene (DPYD) have been associated with impaired enzyme function. The most prominent mutation in the DPD deficient patient group, a mutation in the splicing donor consensus sequence of intron 14, IVS14+1g>a, resulting in a truncated protein, has been observed in the Caucasian population at frequencies as high as 0.91%-0.94%. This underlines the need for a test system for DPYD mutations in patients undergoing chemotherapy with 5-FU or with Xeloda. To set up a fast and sensitive method to identify variant DPYD alleles, we analyzed 50 healthy individuals by denaturing high performance liquid chromatography (DHPLC). A primer set spanning the whole coding region and the exon-intron boundaries of DPYD was used. In addition, a cDNA-based assay was developed to rapidly identify the 165 base pair deletion in the corresponding RNA of IVS14+1g>a mutation carriers. The optimal mutation detection was elaborated for each of the PCR fragments. DHPLC analysis detected 5 different genetic alterations occurring in the coding region of the gene, as well as 10 intronic sequence variants, respectively. In conclusion, high-throughput screening for DPYD variants by DHPLC may be a reliable tool in the investigation of the molecular basis of DPD deficiency. Furthermore, it will help to identify patients at risk for toxic side effects upon chemotherapy using 5-FU and will facilitate individual treatment of patients.     

Biological effects of TrkA and TrkB receptor signaling in neuroblastoma

The Trk family consists of three receptor tyrosine kinases, each of which can be activated by one or more of four neurotrophins-NGF, BDNF, NT3 and NT4. Neurotrophins mediate their multiple effects through a number of distinct intracellular signaling cascades regulating such diverse biological responses as cell survival, proliferation and differentiation in normal and neoplastic neuronal cells. Expression of Trk receptors also plays an important role in the biology and clinical behavior of neuroblastomas. High expression of TrkA is present in neuroblastomas with favorable biological features and highly correlated with patient survival, whereas TrkB is mainly expressed on unfavorable, aggressive neuroblastomas. This short review discusses recent data on the biological roles of TrkA and TrkB signaling in neuroblastoma.     

Prognostic Impact of HIF-1α Expression in Patients with Definitive Radiotherapy for Cervical Cancer

PURPOSE: To investigate the relationship between the hypoxia-inducible factor-(HIF-)1alpha expression in tumor tissue, tumor oxygenation and hemoglobin levels in patients with advanced cervical cancers prior to radiotherapy and the effect on clinical outcome. PATIENTS AND METHODS: The investigation included 44 patients who underwent definitive radiotherapy for advanced cervical cancers between May 1995 and March 1999. Tumor biopsies were taken prior to treatment, and HIF-1alpha expression was determined by immunohistochemistry. In the same tumor area, tumor tissue oxygenation (pO2) was measured using the Eppendorf device. RESULTS: The 5-year cancer-specific survival of all patients was 60%. Twelve of 44 tumor specimens were HIF-1alpha-negative with a significantly better 5-year survival (92 +/- 8%) versus 32 patients who were HIF-1alpha-positive (45 +/- 10%; p < 0.02). There was no correlation between HIF-1alpha expression and tumor oxygenation (p = 0.57 both for pO2 median and hypoxic fraction < 5 mmHg vs. HIF-1alpha expression). However, patients with hemoglobin levels < 11 g/dl showed elevated HIF-1alpha expression compared to patients with hemoglobin levels > 12.5 g/dl (p = 0.04). Furthermore, HIF-1alpha correlated with vascular endothelial growth factor expression (p = 0.002). In a multivariate Cox regression model, HIF-1alpha expression (relative risk [RR] = 7.5; p = 0.05) revealed an increased risk of tumor-related death. CONCLUSION: The study indicates, that endogenous tumor markers such as HIF-1alpha may serve as prognostic markers of clinical outcome concerning cervical cancer after primary radiotherapy.     

Intermittent Use of Amifostine during Postoperative Radiochemotherapy and Acute Toxicity in Rectal Cancer Patients

Purpose: Amifostine has been shown to be able to reduce acute radiation toxicity of administered daily prior to radiation during a course of a conventionally fractionated radiotherapy. A disadvantage is the necessity of daily intravenous injection. We have used amifostin in patients undergoing adjuvant radiochemotherapy for rectal cancer. Amifostine was administered only in the first and fifth week of radiotherapy together with 5-FU chemotherapy. The objective was to determine whether the intermittent use of amifostine may be effective in reducing acute radiation toxicity. Patients and Methods: From September 1997 through October 1998, 30 patients with stage II/III rectal cancer underwent postoperative radiochemotherapy at our department. All patients had undergone curative (R0) resection and received 50.4 Gy to the pelvis with a 3-field technique using a belly board followed by a boost of 5.4 Gy to the presacral space in conventional frationation with 1.8 Gy per fraction. 5-FU chemotherapy was administered as 120-hours continuous infusion in the first and fifth radiation week via a central venous catheter in a daily dosage of 1 000 mg/m². All patients were offered to participate in a phase-II study using additional amifostine. Fifteen patients participated and received 500 mg amifostine daily on chemotherapy days (days 1 to 5 and 29 to 33) immediately prior to the daily radiation fraction. Fifteen patients did not participate and served as non-randomized control. The study was approved by the ethical committee of the Martin-Luther-University and informed consent was obtained from all patients. Results: The distribution of patients' characteristics and prognostic parameters was comparable in both groups. Side effects of amifostine were mild and included hypotension (53% grade I, 7% grade II) and nausea (47% grade I, 13% grade II). Antiemetics were not routinely used. All patients completed radiochemotherapy plus amifostine without unplanned breaks or dose reductions. One patient developed a cerebral infarction which was considered to be not related to the use of amifostine. As compared to the non-randomized control group, patients with additional amifostine had less acute skin and bowel toxicity (maximum erythema score 1.47ǂ.64 without vs. 0.87ǂ.52 with amifostine, p = 0.009 and maximum diarrhea score 1.07ǃ.03 vs 0.40ǂ.63, p = 0.044). Oral 5-FU-related mucositis and hematological toxicity were not significantly different. Conclusions: In this phase-II study, amifostine significantly reduced acute skin and bowel toxicity of adjuvant chemoradiation in patients with rectal cancer even if the drug was administered only intermittently and not during the whole course of radiotherapy. This finding might be important with regard to intense combined regimes and should be further investigated. Hintergrund: Amifostin ist in den letzten Jahren in mehreren Phase-II/III-Studien als Radioprotektor eingesetzt worden. Dabei zeigte sich eine Verringerung der Xerostomie bei Bestrahlungen im Kopf-Hals-Bereich. Ein Effekt auf Mukositis wurde bisher nicht belegt. Wir haben Amifostin in einer Phase-II-Studie bei Patienten mit Rektumkarzinomen während der postoperativen Radiochemotherapie eingesetzt, aber das Präparat nur in den zwei Chemotherapiewochen gegeben. Es sollte geprüft werden, ob dieser intermittierende Applikationsmodus klinisch wirksam sein könnte. Patienten und Methodik: Zwischen September 1997 und Oktober 1998 wurden 15 Patienten mit postoperativer Radiochemotherapie wegen eines Rektumkarzinoms in die offene Phase-II-Studie eingebracht. Die Radiochemotherapie erfolgte nach den Empfehlungen der Deutschen Krebsgesellschaft (28 Fraktionen großvolumig mit 1,8 Gy in Drei-Felder-Technik, drei Fraktionen Boost auf Sakrum und Präsakralregion, zwei Kurse 5-FU mit 1000 mg/m² pro Tag als 120-Stunden-Dauerinfusion in Woche 1 und 5). Amifostin wurde nur an den Chemotherapietagen (Tage 1 bis 5 und 29 bis 33) in einer Dosis von jeweils 500 mg direkt vor der täglichen Bestrahlungsfraktion intravenös appliziert. Die Zustimmung der Ethikkommission der Martin-Luther-Universität lag vor. Während des Studienzeitraums wurden weitere 15 Patienten mit Rektumkarzinom, die die Einschlusskriterien erfüllten, aber an der Studie nicht teilnehmen wollten, mit einer identischen Radiochemotherapie ohne Amifostin behandelt; diese dienten als nicht randomisierte Kontrollgruppe. Ergebnisse: Alle Patienten beendeten die Therapie ohne Komplikationen oder ungeplante Unterbrechungen. Die Toxizität von Amifostin war mild (Hypotension Grad I in 53% und Grad II in 7%, Nausea Grad I in 47% und Grad II in 13%). Patienten mit Amifostin hatten im Vergleich zur nicht randomisierten Kontrollgruppe signifikant weniger akute Nebenwirkungen an der Haut und am Darm (maximaler Erythem-Score 1,47ǂ.64 ohne vs. 0,87ǂ,52 mit Amifostin, p = 0,009 und maximaler Diarrhö-Score 1,07ǃ,03 ohne vs. 0,40ǂ,63 mit Amifostin, p = 0,044). Hämatologische Toxizität und orale 5-FU-Mukositis waren nicht signifikant verschieden. Schlussfolgerungen: In dieser Phase-II-Studie ergeben sich Hinweise für eine mögliche klinische Effektivität von Amifostin auch bei intermittierender Gabe während einer Radiochemotherapie bei Patienten mit Rektumkarzinom.     

Merkel cell carcinoma: molecular pathogenesis,clinical features and therapy

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin. The incidence of this rare tumor is increasing rapidly; the American Cancer Society estimates for 2008 almost 1500 new cases in the U.S. Thus, the incidence of MCC will exceed the incidence of cutaneous T‐cell lymphoma. Moreover, the mortality rate of MCC with 33% is considerably higher than that of cutaneous melanoma. These clinical observations are especially disturbing as we are only recently beginning to understand the pathogenesis of MCC. For the same reason, the therapeutic approach is often unclear; reliable data are only available for the therapy of locoregional disease.