Characterization of drug metabolism enzymes in estrogen-induced kidney tumors in male Syrian hamsters

In an attempt to characterize metabolism enzymes of the estrogen-induced kidney tumor in male Syrian hamsters, the activities of enzymes involved in drug and glutathione metabolism were determined in tumor tissue. Kidney tumors were induced in male Syrian hamsters by treatment with estradiol for 8 months. Cytochrome P-450 and cytochrome b5 concentrations in tumors were below detectable levels. However, when cytochrome P-450-mediated oxidation was analyzed by product formation assays, the oxidation of E-diethylstilbestrol to diethylstilbestrol-4',4"-quinone by tumor microsomes was 10-20% of the rate found in control microsomes. In kidney tissue surrounding estrogen-induced tumors, cytochrome P-450 and b5 contents were 50-60% less than those in untreated kidney. Activities of reducing enzymes of drug metabolism (cytochrome P-450, cytochrome b5 and NADH:cytochrome c reductases), glutathione metabolism enzymes (glutathione peroxidase, glutathione transferase, glutathione reductase, and gamma-glutamyl transpeptidase), and free radical scavenging enzymes (superoxide dismutase, catalase, and quinone reductase) in tumor were significantly lower than in untreated kidney tissue. The activities of these enzymes in renal tumor surrounding tissue were between those observed in tumor and control kidney. Glucose-6-phosphate dehydrogenase activity was increased by 50% in surrounding tissue and 430% in tumor compared to values in untreated controls. The decreased enzyme activity levels in hormone-exposed tissue surrounding tumors likely represented an adaptation of this tissue to the neoplastic environment induced by chronic estrogen treatment.     

Molecular cytogenetic characterization of the mantle cell lymphoma cell line GRANTA-519

Combining fluorescence R-banding, fluorescence in situ hybridization and spectral karyotyping allowed us to precisely define chromosomal breakpoints, gains, losses and a newly detected amplification in the human mantle cell lymphoma (MCL) cell line GRANTA-519. GRANTA-519 is characterized by the t(11;14)(q13;q32) resulting in overexpression of cyclin D1, a key player in cell cycle control. Hitherto unresolved complex rearrangements involve 1p, 1q, 3cen, 9p, 11q, 12p, 12q, 16p, 17p, and 18cen. Moreover, a 4- to 6-fold gain of sequences on 18q leads to a low-level amplification of the BCL2 gene and to an overexpression of the BCL2 protein. These results provide the basis for the identification of not only candidate oncogenes responsible for MCL in gained regions, but also for the identification of putative tumor suppressor genes in commonly deleted regions like 1p22, which would eventually enable functional studies of these genes.     

Tetrasomy 12pter-12p13.31 in a girl with partial Pallister-Killian syndrome phenotype

A dysmorphic patient was shown to carry a small supernumerary marker chromosome. Multicolor, centromere-multicolor and regular FISH experiments proved the marker to be an analphoid 12pter derived isochromosome. Microdissection of the marker followed by reverse painting and array CGH analysis showed that the isochromosome contains approximately 6 Mb of 12pter-12p13.31 derived sequence. This is only the second report of a marker with a neocentromere 12pter and the molecular fine mapping of the duplicated region further refines the 12p region defining the Pallister-Killian syndrome phenotype. In addition, we show the feasibility of using microdissected chromosomes or chromosomal fragments to molecularly map the chromosomal breakpoints on array CGH. This technology may aid in the identification of chromosomal translocation breakpoints.     

A long distance-PCR derived FISH probe detects a deletion between p15 and p16 in CML and T-ALL patients

The tumor suppressor genes p15INK4B and p16INK4A, located in the chromosomal region 9p21, are frequently inactivated by homo- or hemizygous deletions, point mutation or promotor methylation in various types of cancer. No commercial probe is yet available that allows the detection of such deletions by FISH. Long distance (LD)-PCR was successfully used to generate a FISH probe, that covers a sequence stretch of 11.68 kb, located between the tumor suppressor genes p15 and p16. The LD-PCR amplicon was cloned and biotinylated by DOP-PCR (degenerated oligonucleotide primed-PCR) or nick translation. The FISH probe was hybridized on different samples of 16 patients with leukemia (3 T-ALL, 13 CML) and normal controls. Loss of at least one FISH-signal was found in 2/3 (67%) of the T-ALL- and 2/13 (15%) of the CML-cases. The new FISH probe presented here was proven to be advantageous for the detection of deletions in chromosomal region 9p21, especially between p15 and p16.     

Typical and partial cat eye syndrome: identification of the marker chromosome by FISH

Three children are reported with typical cat eye syndrome (CES) and three more children with partial CES because of absence of coloboma, in which the supernumerary marker chromosome was studied by FISH. Using a genomic library, and also a centromeric and particularly a cosmid probe of 22q11, partial tetrasomy was shown in all cases.     

Differential expression of Neu messenger-RNA and protein in hamster-kidney and estrogen-induced kidney tumors

An inverse relationship between the expression of the neu oncogene and estrogen receptors has been observed in breast cancer patients. In this study, we examined neu expression in the estrogen-induced and -dependent hamster kidney tumors, in kidney and in controls to evaluate the usefulness of this animal model far studying the regulation of genes important in hormonal cancer. The expression of neu mRNA was analyzed by Northern analysis and Neu oncoprotein localization by immunocytochemistry. The Neu oncoprotein was detected in several segments of proximal and distal kidney tubules, the loops of Henle and the parietal epithelial cells of Bowman's capsule but not in the tumor. neu mRNA was expressed in renal tissue after estrogen treatment and in untreated controls, but not in kidney tumors. The absence of Neu oncoprotein and mRNA from those cell types that have previously been shown to overexpress estrogen receptors in response to estrogen, suggests that the estrogen receptor and neu genes are interdependent in this tumor system, which may thus be a useful animal model for studying the regulation of neu by estrogens.     

Endoscopy in Barrett's oesophagus: adherence to standards and neoplasia detection in the community practice versus hospital setting

Objective. Potential process differences between hospital and community‐based endoscopy for Barrett’s oesophagus have not been examined. We aimed at comparing adherence to guidelines and neoplasia detection rates in medical centres (MC) and community practices (CP). Design. Retrospective analysis. Setting. All histologically confirmed Barrett cases seen over a 3‐year period in six MC and 19 CP covering a third of all upper gastrointestinal endoscopies (n = 126 000) performed annually in Berlin, Germany. Main outcome measure. Rate of relevant neoplasia (high‐grade intraepithelial neoplasia or more) in both settings in relation to adherence to standards. Results. Of 1317 Barrett cases, 66% were seen in CP. CP patients had a shorter mean Barrett length (2.6 cm vs. 3.8 cm; P < 0.001) with fewer biopsies taken during an examination (2.5 vs. 4.1 for Barrett length ≤2 cm; P < 0.001). CPs also provided fewer complete esophagogastroduodenoscopy documentation (25.1% vs. 57.8%, P < 0.001). Neoplasias were found more commonly in MCs compared to CPs (9.2% vs. 0.8%; P < 0.001). However, on exclusion of all referred patients with known neoplasia (65%) or those examined for other reasons (27.5%), the detection rate at MCs decreased to 1.3%, not different from the one seen at CPs (0.8%, P = 0.43). Only 13% were found during surveillance, but 57% were diagnosed at an early stage. Conclusions. Referral bias and not better adherence to guidelines could explain the higher neoplasia prevalence in Barrett’s oesophagus at hospital centres. Despite a generally poor adherence to guidelines, most neoplasias found were at an early and potentially curable stage.