Avian Pathol: Novel criteria for the diagnosis of Marek's disease virus-induced lymphomas.

Several novel criteria have been tested to assist in the differential diagnosis of tumors induced by Marek's disease virus (MDV) from those induced by avian leukosis virus (ALV) and reticuloendotheliosis virus (REV). A collection of tumors induced by inoculation of specific strains of MDV, ALV, and REV, alone or in combination, were tested for quantification of MDV DNA by real-time polymerase chain reaction, expression of the MDV oncogene Meq, expression of several cell markers associated with transformation (CD30, Marek's disease-associated surface antigen, and p53), and level of DNA methylation in the tumor cells. In addition, tissues latently infected with MDV and noninfected tissues were tested as controls. Tumors induced by MDV had about 102-fold more copies of MDV DNA than either tissues latently infected by MDV or tumors induced by retrovirus in MDV-vaccinated chickens. Moreover, the MDV antigen Meq was consistently expressed in all MDV tumors, but it could not be detected in tissues latently infected with MDV or in tumors induced by retrovirus in MDV-vaccinated chickens. Other markers studied were not specific for MDV and, therefore, had limited value for diagnosis. Nonetheless, some of these markers might have potential value in research, as they will help to identify transformed cells.

2005;34:332-340.