Transmission of canine transmissible venereal tumour between two dogs in the UK.

Canine transmissible venereal tumour (CTVT) is a contagious cancer spread by transfer of living cancer cells. Occasional cases are observed in the UK in dogs imported from endemic regions. Here, we report a case of imported canine transmissible venereal tumour that was transmitted to a second dog within the UK. Transmission of genital canine transmissible venereal tumour occurred despite neutered status of the second dog. The aggressive course of disease in both cases, which included metastasis, resistance to therapeutic interventions and ultimate euthanasia of both dogs, is described. The diagnosis of canine transmissible venereal tumour was made using a combination of cytology, histology, immunohistochemistry and PCR to detect the LINE-MYC rearrangement. Practitioners unfamiliar with canine transmissible venereal tumour are reminded of this disease of concern, particularly when imported dogs are placed in multi-dog households, irrespective of neuter status.

Evaluation of a genetic assay for canine transmissible venereal tumour diagnosis in Brazil.

The canine transmissible venereal tumour (CTVT) is a transmissible cancer that is spread between dogs by the allogeneic transfer of living cancer cells. The infectious agents in CTVT are the living cancer cells themselves, which are transmitted between dogs during coitus. CTVT first arose several thousand years ago and the disease has a global distribution and is frequently observed in dogs from Brazil. We evaluated the utility of a LINE-MYC quantitative polymerase chain reaction for diagnosis of CTVT cases in Brazil. Our analysis indicated that the LINE-MYC rearrangement was detectable in all CTVT samples but not in their corresponding hosts. This genetic assay proves to be a useful tool for providing a definitive molecular diagnosis of CTVT, which presents with varying degrees of aggressiveness and invasiveness in different host dogs and can therefore be a diagnostic challenge in some specific cases.

Tumor-specific diagnostic marker for transmissible facial tumors of Tasmanian devils: immunohistochemistry studies.

Devil facial tumor disease (DFTD) is a transmissible neoplasm that is threatening the survival of the Tasmanian devil. Genetic analyses have indicated that the disease is a peripheral nerve sheath neoplasm of Schwann cell origin. DFTD cells express genes characteristic of myelinating Schwann cells, and periaxin, a Schwann cell protein, has been proposed as a marker for the disease. Diagnosis of DFTD is currently based on histopathology, cytogenetics, and clinical appearance of the disease in affected animals. As devils are susceptible to a variety of neoplastic processes, a specific diagnostic test is required to differentiate DFTD from cancers of similar morphological appearance. This study presents a thorough examination of the expression of a set of Schwann cell and other neural crest markers in DFTD tumors and normal devil tissues. Samples from 20 primary DFTD tumors and 10 DFTD metastases were evaluated by immunohistochemistry for the expression of periaxin, S100 protein, peripheral myelin protein 22, nerve growth factor receptor, nestin, neuron specific enolase, chromogranin A, and myelin basic protein. Of these, periaxin was confirmed as the most sensitive and specific marker, labeling the majority of DFTD cells in 100% of primary DFTD tumors and DFTD metastases. In normal tissues, periaxin showed specificity for Schwann cells in peripheral nerve bundles. This marker was then evaluated in cultured devil Schwann cells, DFTD cell lines, and xenografted DFTD tumors. Periaxin expression was maintained in all these models, validating its utility as a diagnostic marker for the disease.

Clonally transmissible cancers in dogs and Tasmanian devils.

Tasmanian devil facial tumor disease (DFTD) and canine transmissible venereal tumor (CTVT) are the only known naturally occurring clonally transmissible cancers. These cancers are transmitted by the physical transfer of viable tumor cells that can be transplanted across histocompatibility barriers into unrelated hosts. Despite their common etiology, DFTD and CTVT have evolved independently and have unique life histories and host adaptations. DFTD is a recently emerged aggressive facial tumor that is threatening the Tasmanian devil with extinction. CTVT is a sexually transmitted tumor of dogs that has a worldwide distribution and that probably arose thousands of years ago. By contrasting the biology, molecular genetics and immunology of these two unusual cancers, I highlight the common and unique features of clonally transmissible cancers, and discuss the implications of clonally transmissible cancers for host-pathogen evolution.

The expanding universe of noncoding RNAs.

The 71st Cold Spring Harbor Symposium on Quantitative Biology celebrated the numerous and expanding roles of regulatory RNAs in systems ranging from bacteria to mammals. It was clearly evident that noncoding RNAs are undergoing a renaissance, with reports of their involvement in nearly every cellular process. Previously known classes of longer noncoding RNAs were shown to function by every possible means-acting catalytically, sensing physiological states through adoption of complex secondary and tertiary structures, or using their primary sequences for recognition of target sites. The many recently discovered classes of small noncoding RNAs, generally less than 35 nucleotides in length, most often exert their effects by guiding regulatory complexes to targets via base-pairing. With the ability to analyze the RNA products of the genome in ever greater depth, it has become clear that the universe of noncoding RNAs may extend far beyond the boundaries we had previously imagined. Thus, as much as the Symposium highlighted exciting progress in the field, it also revealed how much farther we must go to understand fully the biological impact of noncoding RNAs.