Genetic and epigenetic characteristics of gastric cancers with JC virus T-antigen

AIM： To clarify the significance of JC virus （JCV） T-antigen （T-Ag） expression in human gastric cancer. METHODS： We investigated the relationship between TAg detected by immunohistochemistry and Epstein- Barr virus （EBV） infection, microsatellite instability （MSI）, and genetic and epigenetic alterations in gastric cancers. Mutations in the p53,β-catenin, K/MS, BRAF, PIK3CA genes were analyzed by PCR- single strand conformation polymorphism and DNA sequencing. Allelic losses were determined by PCR at 7 microsatellite loci. Aberrant DNA methylation was analyzed by MethyLight assay. RESULTS： JCV T-Ag protein expression was found in 49% of 90 gastric cancer tissues. TAg positivity was not correlated with clinicopathological characteristics. TAg expression was detected in a similar percentage of EBV positive cancers （4 of 9, 44%） and EBV negative cancers （35 of 73, 48%）. TAg expression was detected in a significantly lower percentage of MSI-H cancers （14%） than in non MSI-H cancers （55%, P = 0.005）. TAg expression was detected in a significantly higher percentage of cancers with nuclear/cytoplasmic localization of β-catenin （15 of 21, 71%） than in cancers without （42%, P = 0.018）. p53 mutations were detected in a significantly lower percentage of T-Ag positive cancers （32%） than in TAg negative cancers （57%, P = 0.018）. TAg positive gastric cancers showed a significant increase in the allelic losses and aberrant methylation compared with T-Ag negative gastric cancers （P = 0.008 and P = 0.003）. CONCLUSION： The results suggest that JCV T-Ag is involved in gastric carcinogenesis through multiple mechanisms of genetic and epigenetic alterations.

JC virus:A brief review

Proportional to the growth rate of its clinical expression, the last decades have seen an increase on JC Virus diagnosis testing, and on therapeutic and symptoms management plans. Whether isolated or associated to retroviral therapy, the relationship of JC Virus to HIV allowed us to delve a little deeper into the knowledge of its behavior. Now as new immune-modulating and immune-suppressing therapies are developed, its clinical expression has become broader and more complexly, thereby our need is to develop more precise diagnosis and therapeutic plans.

Pontocerebellar Progressive Multifocal Leukoencephalopathy. Radiological, Clinical, Histological and Immunohistochemical Findings in a Hematological Patient

Objective: To describe the radiological, histological and immunohistochemical findings in a case of Progressive Multifocal Leukoencephalopathy (PML) affecting the cerebellar peduncles in a patient with chronic lymphocytic leukemia. Patient and Methods: Magnetic Resonance Imaging (MRI), histological picture (H.E., Kluver-Barrera) and immunohistochemical picture (GFAP, neurofilaments, CD68, JC virus) were obtained. Results: 1) Magnetic resonance imaging: Asymmetric and progressive lesions on middle cerebellar peduncles, that were hyperintense in T2/FLAIR, extended towards the pons, had no mass effect and were unmodified after intravenous contrast. 2) Histology: Marked reactive gliosis with cytopathic changes suggesting viral infection, plus demyelination areas with axonal preservation. 3) Immunohistochemistry: Marked positivity for viral (polyoma and JC virus) markers in glial cells showing cytopathic changes. Conclusions: The importance of histological and immunohistochemical diagnosis in everyday assistance;of the collaboration between clinicians, radiologists and pathologists;and the validity of postmortem studies as a key element for research and clinical quality assessment must be stressed.

Progressive Multifocal Leukoencephalopathy—A Case Report in an Immunocompetent Patient

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system due to the reactivation of the JC virus, which usually occurs in immunocompromised patients and is a major opportunistic infection associated with HIV infection. We report a case of a previously healthy patient who was diagnosed with PML.