Viral oncogenes, viruses, and cancer: a third-generation sequencing perspective on viral integration into the human genome

The link between viruses and cancer has intrigued scientists for decades. Certain viruses have been shown to be vital in the development of various cancers by integrating viral DNA into the host genome and activating viral oncogenes. These viruses include the Human Papillomavirus (HPV), Hepatitis B and C Viruses (HBV and HCV), Epstein-Barr Virus (EBV), and Human T-Cell Leukemia Virus (HTLV-1), which are all linked to the development of a myriad of human cancers. Third-generation sequencing technologies have revolutionized our ability to study viral integration events at unprecedented resolution in recent years. They offer long sequencing capabilities along with the ability to map viral integration sites, assess host gene expression, and track clonal evolution in cancer cells. Recently, researchers have been exploring the application of Oxford Nanopore Technologies (ONT) nanopore sequencing and Pacific BioSciences (PacBio) single-molecule real-time (SMRT) sequencing in cancer research. As viral integration is crucial to the development of cancer via viruses, third-generation sequencing would provide a novel approach to studying the relationship interlinking viral oncogenes, viruses, and cancer. This review article explores the molecular mechanisms underlying viral oncogenesis, the role of viruses in cancer development, and the impact of third-generation sequencing on our understanding of viral integration into the human genome.

Hepatitis B virus infection status is not associated with poor prognosis in classical Hodgkin lymphoma patients

Few studies focused on the relationship between hepatitis B virus (HBV) infection and classical Hodgkin lymphoma (cHL). This study was to evaluate the impact of HBV infection on the treatment outcome and survival of cHL patients. Clinical data of 352 cHL patients treated with ABVD regimen (doxorubicin, bleomycin, vincristine and dacarbazine) between January 2002 and January 2018 were retrospectively collected. According to HBV infection status, the patients were divided into three groups: with HBV infection [hepatitis B surface antigen (HBsAg)-positive], with past HBV infection [HBsAg-negative but anti-hepatitis B core antigen (anti-HBc)-positive], and without HBV infection (HBsAg-negative and anti-HBc-negative). The incidence of HBV infection and past HBV infection in cHL patients were 7.4% (26/352) and 16.5% (58/352), respectively. The median age of patients without HBV infection was lower than those in other two groups (p<0.001). The complete remission rates after first-line therapy were different among 3 groups (65.4% for the group with HBV infection, 87.9% for the group with past HBV infection, and 76.1% for the group without HBV infection, respectively, p=0.049). After a median follow-up of 34.6 months, the 3-year progression-free survival rates for the three groups were 69%, 74% and 80%, respectively (p=0.566) and the 3-year overall survival rates were 72%, 91% and 87%, respectively (p=0.096). No HBV reactivation was observed during chemotherapy among 3 groups, but 1 patient in the group with HBV infection experienced delayed HBV reactivation when prophylactic entecavir was discontinued 12 months after the last cycle of chemotherapy. HBV infection status did not affect the clinical outcome and prognosis of cHL patients, especially in the era of prophylactic antiviral therapy.

Eight-year follow-up of patients with myasthenia gravis after thymectomy

PURPOSE

To depict the long-term outcome of patients with myasthenia gravis after thymectomy in combination with immunotherapy, and the factors that may potentially affect the outcome.

METHODS

The 306 patients with myasthenia gravis who underwent extended thymectomy from January 1984 to December 2011 at Tongji Hospital were retrospectively evaluated.

RESULTS

The patients consisted of 174 cases with thymoma and 132 cases without thymoma. Pharmaceutical treatment was tailored for each case during follow-up. Nine patients with thymomatous myasthenia gravis died during the perioperative period, and 297 patients were followed for 8.6 years. By their latest visits, 241 patients (81.1%) gained satisfactory efficacy, 24 cases died (8.1%), and 32 cases (10.8%) remained unchanged or deteriorated. Favorable factors for satisfactory efficacy included the presence of ocular myasthenia gravis before operation, no presence of thymoma, and lack of concomitant diseases. It is interesting to mention that, patients with non-thymomatous myasthenia gravis obtained significantly higher rates of complete stable remission and clinical remission than the patients with thymomatous myasthenia gravis.

CONCLUSIONS

Extended thymectomy combined with immunotherapy is a preferred treatment with a satisfactory long-term remission rate. Patients with non-thymomatous myasthenia gravis have a much more promising prognosis than the patients with thymomatous myasthenia gravis. However, appropriate caution must be taken to discontinue pharmaceutical therapy as relapse remains a major concern after a patient who has already undergone thymectomy becomes symptom-free.

Fatty acid compositions of red blood cell phospholipids in children with autism

We compared the compositions of fatty acids including n-3, n-6 polyunsaturated fatty acids, trans- and cis-monounsaturated fatty acids, and saturated fatty acids in the red blood cell membranes of 40 children with autism (20 with early onset autism and 20 with developmental regression) and age-matched, 20 typically developing controls and 20 subjects with non-autistic developmental disabilities. The main findings include increased levels of eicosenoic acid (20:1n9) and erucic acid (22:1n9) in autistic subjects with developmental regression when compared with typically developing controls. In addition, an increase in 20:2n6 and a decrease in 16:1n7t were observed in children with clinical regression compared to those with early onset autism. Our results do not provide strong evidence for the hypothesis that abnormal fatty acid metabolism plays a role in the pathogenesis of autism spectrum disorder, although they suggest some metabolic or dietary abnormalities in the regressive form of autism.

The clinical study and HLA genotyping of 112 familial myasthenia gravis patients

One hundred and twelve cases of familial myasthenia gravis (MG) from 44 families selected from 2100 patients with MG diagnosed since 1983 in the Department of Neurology were studied. The clinical pictures and immunological features of the patients showed a great resemblance to those of sporadic cases. The pedigree analysis disclosed that the hereditary patterns of familial patients were basically Mendellian autosomal inheritance. Many predisposing factors such as fever, infection, use of aminoglycoside or vaccines, played an important role in presenting the phenotype of subclinical cases. The HLA genotyping suggested that the complement polymorphism C4A * 4, the complotype S42, and the genes 0901 and 1301 of DRB1 allele, were related to the pathogenesis of MG. It was concluded that the phenotype of MG may be the result of interaction between hereditary defects and environmental factors.

Constitutive Cdc25B tyrosine phosphatase activity in adult brain neurons with M phase-type alterations in Alzheimer's disease

The Cdc2/cyclin B kinase is a critical regulator of mitosis that is normally absent from terminally differentiated neurons of adult brain. However, unscheduled expression and activation of Cdc2/cyclin B has been seen in neurons undergoing degeneration in Alzheimer's disease. The presence of this mitotic kinase correlates with accumulation of mitotic phosphoepitopes in protein components of the hallmark neurofibrillary tangles. Of importance to the pathogenic mechanism of Alzheimer's disease is the striking appearance of Cdc2/cyclin B and mitotic phosphoepitopes prior to neurofibrillary tangle formation, which has suggested that a misappropriate mitotic cascade initiates and mediates the neurodegenerative process. To explain the atypical activation of Cdc2/cyclin B in degenerating neurons we have investigated the enzyme responsible for Cdc2/cyclin B activation in mitotic cells, i.e. the Cdc25B tyrosine phosphatase, in Alzheimer's disease brain. Although the enzyme appeared abundant in affected neurons, it was also evident in unaffected neurons of Alzheimer's disease and control brain. Thus, we have found, surprisingly, that Cdc25B is a normal constituent of adult brain neurons, with detectable basal levels of activity. In Alzheimer's disease the levels and activity of the enzyme are elevated, and the active enzyme predominates in the cytoplasmic compartment of neurons. Consistent with these M phase-type changes, Cdc25B displays increased immunoreactivity towards the MPM-2 mitotic phosphoepitope antibody. We propose that aberrant expression of Cdc2/cyclin B in Alzheimer's disease leads to potentiation of mitotic activation mediated by constitutive neuronal Cdc25B activity. As a result, various downstream indices of mitotic events are generated, eventually culminating in neurodegeneration. Our data also suggest that Cdc25B is functional in normal post-mitotic neurons lacking the mitotic Cdc2/cyclin B, but it does not appear to influence the activity of Cdk5, a Cdc2-like kinase that is particularly enriched in brain.

[Mononuclear cell subsets in the peripheral blood of patients with myasthenia gravis]

With the use of the Wuhan series of monoclonal anti-lymphocyte antibodies, the peripheral blood mononuclear cell subpopulations in 104 patients with myasthenia gravis were studied. Before treatment, the mean T4/T8 ratio was higher and the percentage of WuT8+ cells (suppressor T cells) was lower in patients than in the controls. Furthermore, they also showed a higher number of B cells and abnormal lymphocytes (including immature thymocytes and Tac cells) in the blood. In this series 50 cases after oral prednisone treatment and 10 cases following thymectomy revealed normal ranges of mean T4/T8 ratio and WuT8+ cells. Besides, the number of B cells and immature thymocytes in them reduced significantly.