the mechanism of transformation by RNA viruses. Benyesh-Melnick and co-workers describe the presence of DNA in purified murine leukemia-sarcoma virus preparations, suggesting that, in addition to unexpectedly complex enzymatic machinery, some tumor viruses may contain more than one type of nucleic acid. Several groups analyze differences in the membranes of transformed and normal cells. Burger,...

been made by using model systems of limited complexity, such as cancer cells in vitro and oncogenic viruses. The use of cell cultures avoided the complexity of the whole animal but not the complexity of the animal genome. The use of oncogenic viruses seemed to circumvent this complexity by replacing it with the extraordinary simplicity of the viral genome. This simplicity made the study of viru...

Background: The present study sought to investigate molecular evidence for association between the presence of herpes simplex virus (HSV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) in CRC and colorectal polyp by using the PCR method in Iran. Methods: In this analytical case-control study, we selected 15 patients with CRC, 20 patients with colorectal polyp, and 35 patients without mali...

Breast cancer is the most acute worldwide healthcare problem. Its incidence rising. Development of this malignant tumor associated with many risk factor, however primary cause disease stays usually obscure. Researches into breast association oncogenic papillomaviruses have been conducted for three decades, yet there no definite conclusion on Actuality issue these viruses increases times develop...

Studies of cell transformation by RNA and DNA tumor viruses by DNA-RNA hybridization and extension of these techniques to analysis of human cancer tissue are reviewed. The molecular hybridization technique, it is suggested, will be useful in further studies of the role of oncogenic RNA and/or DNA viruses in causation of cancer.

Animal viruses, some of which are probably unable to replicate in human cells, could be transmitted to people where they may be linked to tumours currently not attributed to viruses. Several human virus types have oncogenic potential in animals. A potential risk for acquiring such infections by handling and preparation of animal products was analysed against the background of available epidemio...

The data presented in this review reveal the transforming potential and oncogenic capability of herpes simplex viruses in cultured cells and in experimental animals, respectively. Unfortunately, the role of these agents in human cancer, especially cervical, cannot be unequivocally established through the indirect approaches used, but circumstantial evidence that these viruses represent potentia...

Ribonuclease-sensitive DNA synthesis is demonstrated in a cytoplasmic particulate fraction of normal human blood lymphocytes stimulated with phytohemagglutinin, but not in unstimulated lymphocytes. DNA polymerase purified from this fraction does not transcribe the heteropolymeric regions of 70S RNA from RNA tumor viruses, thus distinguishing this enzyme from the RNA-directed DNA polymerase (rev...

Adeno-associated virus (AAV) is a nonpathogenic, single-stranded DNA virus belonging to the parvoviridae family. Onco-suppressive properties of AAV against adenovirus, a DNA tumor virus, have been well documented. Rep78, a major regulatory protein of AAV, is believed to be responsible for its antioncogenic properties. Most DNA tumor viruses disturb the cell cycle pathways by essentially abrogat...