Canine urothelial carcinoma: genomically aberrant and comparatively relevant.

Urothelial carcinoma (UC), also referred to as transitional cell carcinoma (TCC), is the most common bladder malignancy in both human and canine populations. In human UC, numerous studies have demonstrated the prevalence of chromosomal imbalances. Although the histopathology of the disease is similar in both species, studies evaluating the genomic profile of canine UC are lacking, limiting the discovery of key comparative molecular markers associated with driving UC pathogenesis. In the present study, we evaluated 31 primary canine UC biopsies by oligonucleotide array comparative genomic hybridization (oaCGH). Results highlighted the presence of three highly recurrent numerical aberrations: gain of dog chromosome (CFA) 13 and 36 and loss of CFA 19. Regional gains of CFA 13 and 36 were present in 97 % and 84 % of cases, respectively, and losses on CFA 19 were present in 77 % of cases. Fluorescence in situ hybridization (FISH), using targeted bacterial artificial chromosome (BAC) clones and custom Agilent SureFISH probes, was performed to detect and quantify these regions in paraffin-embedded biopsy sections and urine-derived urothelial cells. The data indicate that these three aberrations are potentially diagnostic of UC. Comparison of our canine oaCGH data with that of 285 human cases identified a series of shared copy number aberrations. Using an informatics approach to interrogate the frequency of copy number aberrations across both species, we identified those that had the highest joint probability of association with UC. The most significant joint region contained the gene PABPC1, which should be considered further for its role in UC progression. In addition, cross-species filtering of genome-wide copy number data highlighted several genes as high-profile candidates for further analysis, including CDKN2A, S100A8/9, and LRP1B. We propose that these common aberrations are indicative of an evolutionarily conserved mechanism of pathogenesis and harbor genes key to urothelial neoplasia, warranting investigation for diagnostic, prognostic, and therapeutic applications.

Shared acquired genomic changes in zebrafish and human T-ALL.

T-cell acute lymphoblastic leukemia (T-ALL) is a challenging clinical entity with high rates of induction failure and relapse. To discover the genetic changes occurring in T-ALL, and those contributing to relapse, we studied zebrafish (Danio rerio) T-ALL samples using array comparative genomic hybridization (aCGH). We performed aCGH on 17 T-ALLs from four zebrafish T-ALL models, and evaluated similarities between fish and humans by comparing all D. rerio genes with copy number aberrations (CNAs) with a cohort of 75 published human T-ALLs analyzed by aCGH. Within all D. rerio CNAs, we identified 893 genes with human homologues and found significant overlap (67%) with the human CNA dataset. In addition, when we restricted our analysis to primary T-ALLs (14 zebrafish and 61 human samples), 10 genes were recurrently altered in > 3 zebrafish cancers and ≥ 4 human cases, suggesting a conserved role for these loci in T-ALL transformation across species. We also conducted iterative allo-transplantation with three zebrafish malignancies. This technique selects for aggressive disease, resulting in shorter survival times in successive transplant rounds and modeling refractory and relapsed human T-ALL. Fifty-five percent of original CNAs were preserved after serial transplantation, demonstrating clonality between each primary and passaged leukemia. Cancers acquired an average of 34 new CNAs during passaging. Genes in these loci may underlie the enhanced malignant behavior of these neoplasias. We also compared genes from CNAs of passaged zebrafish malignancies with aCGH results from 50 human T-ALL patients who failed induction, relapsed or would eventually relapse. Again, many genes (88/164) were shared by both datasets. Further, nine recurrently altered genes in passaged D. rerio T-ALL were also found in multiple human T-ALL cases. These results suggest that zebrafish and human T-ALLs are similar at the genomic level, and are governed by factors that have persisted throughout evolution.

Recent advances in the molecular pathogenesis of Ewing's sarcoma.

Tumor development is a complex process resulting from interplay between mutations in oncogenes and tumor suppressors, host susceptibility factors, and cellular context. Great advances have been made by studying rare tumors with unique clinical, genetic, or molecular features. Ewing's sarcoma serves as an excellent paradigm for understanding tumorigenesis because it exhibits some very useful and important characteristics. For example, nearly all cases of Ewing's sarcoma contain the (11;22)(q24;q12) chromosomal translocation that encodes the EWS/FLI oncoprotein. Besides the t(11;22), however, many cases have otherwise simple karyotypes with no other demonstrable abnormalities. Furthermore, it seems that an underlying genetic susceptibility to Ewing's sarcoma, if it exists, must be rare. These two features suggest that EWS/FLI is the primary mutation that drives the development of this tumor. Finally, Ewing's sarcoma is an aggressive tumor that requires aggressive treatment. Thus, improved understanding of the pathogenesis of this tumor will not only be of academic interest, but may also lead to new therapeutic approaches for individuals afflicted with this disease. The purpose of this review is to highlight recent advances in understanding the molecular pathogenesis of Ewing's sarcoma, while considering the questions surrounding this disease that still remain and how this knowledge may be applied to developing new treatments for patients with this highly aggressive disease.

Is There a Predisposition Gene for Ewing's Sarcoma?

Ewing's sarcoma is a highly malignant tumor of children and young adults. The molecular mechanisms that underlie Ewing's Sarcoma development are beginning to be understood. For example, most cases of this disease harbor somatic chromosomal translocations that fuse the EWSR1 gene on chromosome 22 with members of the ETS family. While some cooperative genetic events have been identified, such as mutations in TP53 or deletions of the CDKN2A locus, these appear to be absent in the vast majority of cases. It is therefore uncertain whether EWS/ETS translocations are the only consistently present alteration in this tumor, or whether there are other recurrent abnormalities yet to be discovered. One method to discover such mutations is to identify familial cases of Ewing's sarcoma and to then map the susceptibility locus using traditional genetic mapping techniques. Although cases of sibling pairs with Ewing's sarcoma exist, familial cases of Ewing's sarcoma have not been reported. While Ewing's sarcoma has been reported as a 2nd malignancy after retinoblastoma, significant associations of Ewing's sarcoma with classic tumor susceptibility syndromes have not been identified. We will review the current evidence, or lack thereof, regarding the potential of a heritable condition predisposing to Ewing's sarcoma.

Adenovirus detection in Guthrie cards from paediatric leukaemia cases and controls.

Archived neonatal blood cards (Guthrie cards) from children who later contracted leukaemia and matched normal controls were assayed for adenovirus (AdV) C DNA content using two highly sensitive methods. In contrast to a previous report, AdV DNA was not detected at a higher frequency among neonates who later developed leukaemia, when compared with controls.

Controllable formation of nanoscale patterns on TiO2 by conductive-AFM nanolithography.

We report on the nanopatterning of double-bond-terminated silane (5-hexenyltrichlorosilane, HTCS) molecules on titania (TiO2) using conductive atomic force microscopy (AFM). The influences of tip electrostatic potential and scanning velocity, relative humidity and of the repeated application of voltage on the topographic height, width, and hydrophilic and hydrophobic contrast of the resultant patterns were investigated. Tip voltage and tip velocity ( v) were applied between -10 V