Detection of Tumor-Associated Viruses

Only limited numbers of viruses are able to transform human cells to an oncogenic status to induce malignant tumors, while only a few human tumors are associated with chronic viral infection. 

There are eight members of the herpesvirus family able to infect humans HHV-1 (herpes simplex virus 1, HSV-1) HHV-2 (herpes simplex virus 2, HSV-2) HHV-3 (varicella zoster virus,VZV) HHV-4 (Epstein-Barr virus, EBV) HHV-5 (cytomegalovirus, CMV) HHV-6 (human B-cell lymphotrophic virus or roseolovirus) HHV-7 (closely related to HHV-6) HHV-8 (a type of the rhadinovirus). 

The Epstein-Barr virus (EBV H HV-4) and thehumanherpesvirusS (HHV-8) are two members ofthe gamma herpesvirus family, able to induce human tumors. EBV (HHV- 

4) is found in association with different human neoplasia such as Hodgkin s disease, lymphoepithehal carcinoma (nasopharyngeal carcinoma), peripheral T-cell lymphoma and N K/T-celllymphoma. It is also found in about 90% of endemic Burkitt s lymphoma and inup to 30% ofthe sporadic cases. H H V-8 is discovered inassociation with Kaposi s sarcoma, multiple myeloma, primary effusion lymphoma, inflammatory myofibro-blastic tumor (inflammatory pseudotumor) and Castleman s disease. 

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Another useful aspect in oncology is the detection of tumor-assodated viruses, which are important for tumor diagnosis, therapy and dinical follow-up. Using specific primers and probes complementary to virus genomes, provide a powerful and sensitive method to detect many viral genes and oncogenes associated with different types of malignancies such as HPV, EBV, HHV-8 and HCV. 

Hepatic stellate cell activation is also associated with the induction of other liver diseases. In livers of patients with chronic hepatitis, an increased number of activated HSC were detected [87], Recently, an interaction of hepatitis C virus (HCV) with HSC was reported [88], Furthermore, HSC activation is associated with the development of liver tumors, for instance, hepatocellular carcinomas (HCC). Mediators like TGF-a and TGF-P derived from dysplastic hepatocytes... 

The HHV-8 virus is found in association with Kaposi s sarcoma, rare forms of B-cell lymphoma, multiple myeloma, primary effusion lymphoma, Castleman s disease and sarcoidosis. HHV-8 has been detected in the majority of bone marrow samples taken from multiple myeloma patients. Recently HHV-8 was described in association with the pulmonary and extrapulmonary inflammatory pseudotumor (inflammatory myoflbroblastic tumor). 

Nasopharyngeal carcinoma (NPC) and Burkitt lymphoma are strongly associated with Epstein-Barr virus (EBV) infection (lARC 1997) and account for approximately 1% of world cancer cases (lARC 2003a). NPC is an epithelial tumor with a high prevalence in southern China, where the incidence rate is about 25-50 per 100,000 people-year and 100-fold higher than that in the Western world (Jeannel et al. 1999 McDermott et al. 2001). Latent EBV infection is detected in cancer cells of virtually all cases of undifferentiated NPC in endemic regions (lARC 2003 a Tsai... 

Following the early observation of Klenk and Yamakawa and their associates, the presence of sialic acid residues at the surface of numerous cells was established, either by action of neuraminidase followed by determination of the cell electrophoretic mobility or by determination of the sialic acid released. For example, sialic acid residues were detected at the surface of EMich ascites tumor cells (Wallach and Eylar, 1961 Cook et aL, 1962), hamster kidney fibroblasts transformed by polyoma virus (Forrester et aL, 1964), squamous epithelial cells (Berwick and Coman, 1962), solid and ascites sarcoma cells (Cook et aL, 1963 Wallach and de Perez Esandi, 1964), normal and malignant rat liver cells (Kalant et aL, 1964), cells from human bronchial carcinoma, cells from rat myeloma, HeLa cells, and L-strain mouse fibroblasts (Fuhrmann etaL, 1962). 

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