| Popis: |
Several factors have been implicated in the etiology of human breast cancer. The potential involvement of members of the Retroviridae family of viruses has represented a major focus of investigation (1 for review). This is primarily a result of studies of mammary cancer in laboratory mice, where infectious type-B oncoviruses (mouse mammary tumor virus, MMTV) have been shown to be associated with a high incidence of mammary tumors. With the exception of species of the genus Mus (2,3) and Rattus (4), attempts to identify DNA sequences related to the MMTV genome in DNAs of all other mammalian species tested have not been consistently successful (5,6). Other studies (7,8), using liquid hybridization and MMTV cDNA probes, reported the presence of RNA species, in human mammary tumors, related to the viral genome. The lack of uniform probes, the potential for contamination of cDNA preparations with cellular DNA or RNA, and the relative lack of sensitivity of liquid hybridization techniques made these findings difficult to interpret. |
