In situ hybridization is a method for detecting specific nucleic acid sequences within individual cells. This technique permits visualization of viral nucleic acid or gene expression in individual cells within their histologic context. In situ hybridization is based on the complementary binding of a labeled nucleic acid probe to complementary sequences in cells or tissue sections, followed by visualization of target sequences within the cells. It has been used widely for the detection of viral nucleic acid sequences within individual cells. This review will define the technical approaches of in situ hybridization and its current application to detect viral nucleic acids within formalin-fixed, paraffin-embedded tissue samples, with special reference to the Epstein-Barr virus.
A number of methods exist to detect levels of telomerase activity and the presence of telomerase subunits in a variety of tissues. As telomerase activation seems to be an important step in tumorigenesis, accurate detection of the presence and activity of the enzyme and its subunits is vital. The original method of detecting telomerase activity was developed by Kim and coworkers in 1994, and was termed the telomeric repeat amplification protocol. This assay led to a staggering increase in the number of telomerase-associated publications in scientific journals (85 publications from 1974-1994, 5063 publications from 1994-2004). A number of methods have been described to detect telomeres and to measure their length, with the standard measurement of telomere length performed using a modification of the Southern blot protocol. RNA in situ hybridization can be performed to detect levels of the RNA component of telomerase, and standard in situ hybridization and immunohistochemistry can be applied to examine expression levels and localization of the catalytic subunit of the enzyme. Reverse transcriptase PCR has also been applied to assess expression levels of the telomerase components in various tissues. This review provides a synopsis of telomeres, telomerase, telomerase and cancer, and finally, methods for the detection of telomerase in cancer.
The effect of infection with teratogenic viruses at early stages of pregnancy is not fully understood. This study aimed to look at the effect of infection with teratogenic viruses such as bovine viral diarrhea virus (BVDV) and border disease virus (BDV), on early stage embryos at the hatched blastocyst stage. BVDV and BDV are known to cross the placenta of infected mothers and lead to congenital defects and death of developing fetuses. This study can be a good model for better understanding the effects of other teratogenic viruses such as Rubella virus in humans.
Many studies in the literature have shown that Epstein-Barr virus (EBV) is associated with several human lymphoid and epithelial malignancies. However, the prevalence of EBV in non-Hodgkin lymphoma (NHL) of the lower gastrointestinal (GI) tract has not been fully elucidated.
The tumor suppressor gene p15(INK4b) is a cyclin-dependent kinase inhibitor, in which its inactivation has been determined in primary tumors and in several tumor-derived cell lines. The precise role of p15(INK4b) protein expression in cutaneous squamous cell carcinoma (SCC) is currently not known. In a previous study, we have shown the frequent occurrence of allelic imbalance/loss of heterozygosity in cutaneous SCC using two microsatellite markers flanking the p15(INK4b) gene. This study is a continuation of our previous study and aims to determine the possible role of p15(INK4b) protein expression in the genesis of cutaneous SCC. P15(INK4b) protein expression was determined using immunohistochemical approach in 107 cases of cutaneous SCC tissue arrays and 19 cases of normal human skin tissues. The expression of p15(INK4b) was significantly reduced in the cutaneous SCC cases as compared with normal human skin (p = 0.017 and p < 0.05). However, there were no significant relationship between clinicopathologic variables of the patients (age, sex and tumor grade) and p15(INK4b) protein expression. The absence of p15(INK4b) expression in the majority of tissue microarray cores of cutaneous SCC indicated that p15(INK4b) could possibly be involved in the pathogenesis of cutaneous SCC.