Lack of association of cytomegalovirus with adenocarcinoma of the colon

Cytomegalovirus in Haematological Tumours

The exquisite coupling between herpesvirus and human beings is the result of millions of years of relationship, coexistence, adaptation, and divergence. It is probably based on the ability to generate a latency that keeps viral activity at a very low level, thereby apparently minimising harm to its host. However, this evolutionary success disappears in immunosuppressed patients, especially in haematological patients. The relevance of infection and reactivation in haematological patients has been a matter of interest, although one fundamentally focused on reactivation in the post-allogeneic stem cell transplant (SCT) patient cohort. Newer transplant modalities have been progressively introduced in clinical settings, with successively more drugs being used to manipulate graft composition and functionality. In addition, new antiviral drugs are available to treat CMV infection. We review the immunological architecture that is key to a favourable outcome in this subset of patients. Less is known about the effects of herpesvirus in terms of mortality or disease progression in patients with other malignant haematological diseases who are treated with immuno-chemotherapy or new molecules, or in patients who receive autologous SCT. The absence of serious consequences in these groups has probably limited the motivation to deepen our knowledge of this aspect. However, the introduction of new therapeutic agents for haematological malignancies has led to a better understanding of how natural killer (NK) cells, CD4+ and CD8+ T lymphocytes, and B lymphocytes interact, and of the role of CMV infection in the context of recently introduced drugs such as Bruton tyrosine kinase (BTK) inhibitors, phosphoinosytol-3-kinase inhibitors, anti-BCL2 drugs, and even CAR-T cells. We analyse the immunological basis and recommendations regarding these scenarios.

Viruses in colorectal cancer

Increasing evidence suggests that microorganisms might represent at least highly interesting cofactors in colorectal cancer (CRC) oncogenesis and progression. Still, associated mechanisms, specifically in colonocytes and their microenvironmental interactions, are still poorly understood. Although, currently, at least seven viruses are being recognized as human carcinogens, only three of these – Epstein–Barr virus (EBV), human papillomavirus (HPV) and John Cunningham virus (JCV) – have been described, with varying levels of evidence, in CRC. In addition, cytomegalovirus (CMV) has been associated with CRC in some publications, albeit not being a fully acknowledged oncovirus. Moreover, recent microbiome studies set increasing grounds for new hypotheses on bacteriophages as interesting additional modulators in CRC carcinogenesis and progression. The present Review summarizes how particular groups of viruses, including bacteriophages, affect cells and the cellular and microbial microenvironment, thereby putatively contributing to foster CRC. This could be achieved, for example, by promoting several processes – such as DNA damage, chromosomal instability, or molecular aspects of cell proliferation, CRC progression and metastasis – not necessarily by direct infection of epithelial cells only, but also by interaction with the microenvironment of infected cells. In this context, there are striking common features of EBV, CMV, HPV and JCV that are able to promote oncogenesis, in terms of establishing latent infections and affecting p53‐/pRb‐driven, epithelial–mesenchymal transition (EMT)‐/EGFR‐associated and especially Wnt/β‐catenin‐driven pathways. We speculate that, at least in part, such viral impacts on particular pathways might be reflected in lasting (e.g. mutational or further genomic) fingerprints of viruses in cells. Also, the complex interplay between several species within the intestinal microbiome, involving a direct or indirect impact on colorectal and microenvironmental cells but also between, for example, phages and bacterial and viral pathogens, and further novel species certainly might, in part, explain ongoing difficulties to establish unequivocal monocausal links between specific viral infections and CRC.

Human Cytomegalovirus Reduces Endothelin-1 Expression in Both Endothelial and Vascular Smooth Muscle Cells

Human cytomegalovirus (HCMV) is an opportunistic pathogen that has been implicated in the pathogenesis of atherosclerosis. Endothelin-1 (ET-1), a potent vasoconstrictive peptide, is overexpressed and strongly associated with many vasculopathies. The main objective of this study was to investigate whether HCMV could affect ET-1 production. As such, both endothelial and smooth muscle cells, two primary cell types involved in the pathogenesis of atherosclerosis, were infected with HCMV in vitro and ET-1 mRNA and proteins were assessed by quantitative PCR assay, immunofluorescence staining and ELISA. HCMV infection significantly decreased ET-1 mRNA and secreted bioactive ET-1 levels from both cell types and promoted accumulation of the ET-1 precursor protein in infected endothelial cells. This was associated with inhibition of expression of the endothelin converting enzyme-1 (ECE-1), which cleaves the ET-1 precursor protein to mature ET-1. Ganciclovir treatment did not prevent the virus suppressive effects on ET-1 expression. Consistent with this observation we identified that the IE2-p86 protein predominantly modulated ET-1 expression. Whether the pronounced effects of HCMV in reducing ET-1 expression in vitro may lead to consequences for regulation of the vascular tone in vivo remains to be proven.

Gut microbiota in colorectal cancer: mechanisms of action and clinical applications

Colorectal cancer (CRC) accounts for about 10% of all new cancer cases globally. Located at close proximity to the colorectal epithelium, the gut microbiota comprises a large population of microorganisms that interact with host cells to regulate many physiological processes, such as energy harvest, metabolism and immune response. Sequencing studies have revealed microbial compositional and ecological changes in patients with CRC, whereas functional studies in animal models have pinpointed the roles of several bacteria in colorectal carcinogenesis, including Fusobacterium nucleatum and certain strains of Escherichia coli and Bacteroides fragilis. These findings give new opportunities to take advantage of our knowledge on the gut microbiota for clinical applications, such as gut microbiota analysis as screening, prognostic or predictive biomarkers, or modulating microorganisms to prevent cancer, augment therapies and reduce adverse effects of treatment. This Review aims to provide an overview and discussion of the gut microbiota in colorectal neoplasia, including relevant mechanisms in microbiota-related carcinogenesis, the potential of utilizing the microbiota as CRC biomarkers, and the prospect for modulating the microbiota for CRC prevention or treatment. These scientific findings will pave the way to clinically translate the use of gut microbiota for CRC in the near future.

Profiling of microRNAs modulating cytomegalovirus infection in astrocytoma patients

Astrocytoma is recognized as the most common neoplasm of the brain with aggressive progression. The therapeutic regime for glioblastoma, the most aggressive astrocytoma, often consists of aggressive chemo and radiotherapy. The present holistic approaches, however, have failed to influence the quality life of patients. Therefore, it is necessary to understand the underlying mechanisms of its progression for updated therapeutic evaluation. Human cytomegalovirus (HCMV) is reported to be associated with glioblastoma progression. The hypothesis still remains controversial due to the lack of concrete evidences. Here, we report the profile of miRNAs encoded by human host and the cytomegalovirus (CMV) involved in modulation of CMV infection in surgically resected human astrocytoma tissue samples of various malignancy grades (n = 24). Total RNA from the control brain and tumor tissues was extracted by TriZol reagent. The expression levels of the mature form of miRNA were detected by real-time PCR. Primarily, we found the upregulation of miR-210-3p, miR-155-5p, miR-UL-112-3p, miR-183-5p, and miR-223-5p in high-grade astrocytic tumors as compared with low-grade tumor tissues. miR-214-3p is significantly expressed in control brain tissues and its expression decreased with astrocytoma grade progression. This miRNA was reported to be associated with antiviral proprieties. Among CMV-encoded miRNA, miR-UL-112-3p was significantly upregulated in glioblastoma tissue samples and may be involved in providing immune escape to the virus as well as involved in modulating the immune microenvironment of glioblastoma. Taken together, we conclude the possible involvement of miRNAs in modulating the CMV dependent astrocytoma progression.

Role of Cytomegalovirus and Epstein-Barr virus in Patients with de Novo Colon Cancer after Renal Transplantation

Aims

The development of new effective immunosuppressive agents has provided long-term survival for transplant recipients, thereby increasing the risk of de novo malignancy in chronic immunocompromised hosts. Although de novo post-transplant lymphoproliferative diseases and skin cancer have been shown to have an increased incidence in long-term surviving solid organ transplant recipients, the association with colon cancer is controversial.

Patients and methods

Over a 12-year period, 20 patients (5%) out of 400 renal transplant recipients (treated at the University Hospitals of Udine and Ancona) developed 24 de novo tumors; 11 skin cancers and 13 non-skin cancers. Three patients developed de novo colon cancer. Immunosuppressive therapy was reduced immediately after diagnosis, and all patients were shifted from cyclosporine to rapamicine within 30 days. The tumor was surgically resected with curative intent in 2 cases, and 1 patient had only palliative surgery due to metastatic disease. The postoperative course was uneventful, and all patients maintained normal graft function.

Results

Two of 3 patients died of progression of the neoplasm, within a median time from the diagnosis of 12 months. We analyzed the possible correlations between de novo colon cancer and “serology (hepatitis C virus-hepatitis B virus, HCV-HBV) status'’ infections, cytomegalovirus and Epstein-Barr virus reactivation, episodes of rejection, and blood transfusions.

Conclusions

Differently from other de novo skin and non-skin tumors, our cases developed cytomegalovirus and Epstein-Barr virus reactivation within 3 months of transplantation. Therefore, we suggest a closer follow-up for de novo colon cancer in renal transplants with early cytomegalovirus and Epstein-Barr virus reactivation in order to avoid a delay in diagnosis.

Human cytomegalovirus infection and colorectal cancer risk: a meta-analysis

Human cytomegalovirus infection (HCMV) has been recently considered as a factor for tumorigenesis. The current study used meta-analytical techniques to explore the prevalence of HCMV in tumor tissues and the relationship between human cytomegalovirus and colorectal cancer (CRC) risk. 11 studies detecting HCMV DNA in tumor tissues were included in meta-analysis. The prevalence rate and odds ratio (OR) were two main parameters. The overall prevalence of human cytomegalovirus DNA in tumor tissues were 27.5% (95% CI = 17.2%−37.8%). Binary logistic regression showed that the studies reported before 2010 involving formalin-fixed specimens from patients in developed region represented a lower proportion of HCMV. The tumor tissues had a significantly higher rate of virus infection compared with normal tissues (OR = 6.59, 95% CI = 4.48−9.69, I² = 0%, P = 0.71). Subgroup analysis revealed the prevalence of the virus didn't differ in patients with different tumor stages, in tumor cells with different histologic grades, also in different kinds of specimen (polyp and adenocarcinoma). The results of current study suggested a statistically association between the virus infection and an increased risk of colorectal cancer.

A viral map of gastrointestinal cancers

Cancers of the gastrointestinal tract (GIT) are expected to account for approximately 20% of all cancers in 2017. Apart from their high incidence, GIT cancers show high mortality rates, placing these malignancies among the most prominent public health issues of our time. Cancers of the GIT are the result of a complex interplay between host genetic factors and environmental factors and frequently arise in the context of a continued active inflammatory response. Several tumor viruses are able to elicit such chronic inflammatory responses. In fact, several viruses have an impact on GIT tumor initiation and progression, as well as on patients' response to therapy and prognosis, through direct and indirect mechanisms. In this review, we have gathered information on different viruses' rates of infection, viral-driven specific carcinogenesis mechanisms and viral-related impact on the prognosis of cancers of the GIT (specifically in organs that have an interface with the environment - esophagus, stomach, intestines and anus). Overall, while some viral infections show a strong causal relation with specific gastrointestinal cancers, these represent a relatively small fraction of GIT malignancies. Other types of cancer, like Esophageal Squamous Cell Carcinoma, require further studies to confirm the carcinogenic role of some viral agents.

Clinical relevance between human cytomegalovirus infection and colorectal cancer

AIM: To investigate the clinical relevance between human cytomegalovirus (HCMV) infection and colorectal cancer.

METHODS: The specific immunoglobulin G (IgG) and IgM antibodies against HCMV in sera of colorectal cancer patients (n = 60), patients with colorectal polyps (n = 60) and health controls (n = 60) were detected by chemiluminescence immunoassay. HCMV infection in colorectal cancer tissues and corresponding adjacent normal samples were determined through the detection of UL138 gene by nested PCR and in situ hybridization. The relationships between HCMV infection and clinical features of colorectal cancer were analyzed.

RESULTS: The positive rates of HCMV-IgG in the colorectal cancer group, colorectal polyps group and healthy control group were 95.0% (57/60), 98.3% (59/60), and 96.7% (58/60), respectively; the positive rates of HCMV-IgM were 5.0% (3/60), 1.7% (1/60) and 1.7% (1/60), respectively. There were no statistically significant differences in the positive rates of HCMV-IgG and HCMV-IgM among the three groups. However, there was a significant difference between colorectal cancer tissues and corresponding normal tissues in HCMV-UL138 detection. The positive rates of HCMV-UL138 were 65.6% (19/32) and 62.5% (20/32) in colorectal cancer tissues samples, and 12.5% (4/32) and 9.4% (3/32) in corresponding normal tissues as revealed by nested PCR detection and in situ hybridization, respectively. HCMV infection had no significant association with age, gender, location of mass, tumor size, histological differentiation, metastasis or Dukes stage.

CONCLUSION: HCMV infection is associated with colorectal cancer. Compared with corresponding normal epithelium, the neoplastic epithelium may be preferentially infected by the HCMV. This research suggests that HCMV infection may play a role in the occurrence and development of colorectal cancer.

The oncomodulatory role of human cytomegalovirus in colorectal cancer: implications for clinical trials

Increasing evidence suggests that human cytomegalovirus (HCMV), a beta-herpes virus that chronically infects human beings, is associated with colorectal cancer (CRC). The viral nucleic acids specifically localized to the neoplastic mucosal epithelium of CRC, while tumoral presence of HCMV independently predicted a poor outcome in elderly patients. In the past decade, the concept of “oncomodulation” of HCMV in human cancers has been formulated. In CRC, changes in the tumor microenvironment are closely related to cancer behavior and prognosis, while the underlying mechanism driving these changes remains unclear. As HCMV affects multiple cellular functions, including signal pathways that regulate angiogenesis, apoptosis, cell invasiveness, and anti-cancer immunity, the virus potentially exerts oncomodulatory effects in the tumor microenvironment of CRC. Here, we summarize the current knowledge about the association between HCMV and CRC and suggest future perspectives on both research and anti-cancer therapy of CRC.

Human cytomegalovirus viral load in tumor and peripheral blood samples of patients with malignant gliomas

Malignant gliomas are the most common primary brain tumors in adults. The disease has no known etiology, progresses rapidly, and is fatal despite current therapies. Human cytomegalovirus (HCMV) is a beta herpes virus that is trophic for glial cells and infects 50% to 90% of the adult human population. HCMV-mediated disease in immunosuppressed patients has highlighted the possible role of this virus in the development of other diseases, particularly inflammatory diseases such as vascular diseases, autoimmune diseases, and certain malignancies. Sensitive detection of viral DNA, mRNA, and antigens in tumor tissues, as well as seroepidemiologic evidence, suggest a link between HCMV and several human malignancies. HCMV gene products are proposed to dysregulate multiple cellular pathways involved in oncogenesis, such as cell cycle regulation, apoptosis, migration, and angiogenesis. These theories, currently being researched, suggest that HCMV acts as an oncomodulator in malignancies. We investigated the association between HCMV infection and reactivation, and malignant gliomas. An open, matched case-control, parallel group pilot study was performed in a tertiary referral center. The HCMV viral load in peripheral blood and tumor samples of 19 patients newly diagnosed with glioblastoma multiforme was compared with a matched control cohort comprising 19 patients newly diagnosed with non-malignant brain tumors. There was no significant correlation between peripheral blood and tumor tissue HCMV viral load in patients with glioblastoma multiforme compared to the control cohort. The findings of the present study did not support an oncomodulatory role for HCMV in malignant gliomas.

Human cytomegalovirus preferentially infects the neoplastic epithelium of colorectal cancer: a quantitative and histological analysis

BACKGROUND

It has long been suggested that human cytomegalovirus (HCMV) might be involved in human oncogenesis. However, whether HCMV was associated with colorectal cancer (CRC) was still controversial.

OBJECTIVE

To clarify whether HCMV specifically infects the tumorous tissue of CRC.

STUDY DESIGN

Paired tumor and adjacent non-neoplastic CRC specimens were collected from 163 patients. HCMV DNA was detected and quantified through PCR and quantitative real-time PCR. Virus location was determined by in situ hybridization (ISH) of formalin-fixed paraffin-embedded tissue sections with an HCMV-specific probe.

RESULTS

By PCR, HCMV DNA was detected in 42.3% (69/163) of the tumor specimens, while only 5.6%(14/163) samples of adjacent non-neoplastic tissue were positive for HCMV (p<0.0001). Quantitative real-time PCR in 54 sample pairs revealed significantly higher viral copies in the tumor specimens than the adjacent non-neoplastic tissue specimens (p<0.001). By ISH, the nucleic acids of HCMV were detected in the cytoplasm of neoplastic epithelium. No hybridization was detected in the inflammatory infiltrates, submucosa, or other stromal tissues.

CONCLUSIONS

HCMV preferentially infects the tumor epithelium of CRC. How the virus subsists in and interacts with the microenvironment of tumor epithelium of CRC should be studied.

Infectious causes of colorectal cancer

Colorectal cancer is a major cause of cancer-related morbidity and mortality in the United States and many other regions of the world. Our understanding of the pathogenesis of colorectal cancer, from the precursor adenomatous polyp to adenocarcinoma, has evolved rapidly. Colorectal carcinogenesis is a sequential process characterized by the accumulation of multiple genetic and molecular alterations in colonic epithelial cells. However, the development of colorectal cancer involves more then just a genetic predisposition. External or environmental factors presumably play a significant role, and inflammatory bowel diseases, obesity, alcohol consumption, and a diet high in fat and low in fiber have all been implicated as risk factors for the development of either colonic adenomas or carcinomas. We are becoming increasingly aware of microbes as causes of malignancies. This article reviews the various microbes that have been associated with the development of colorectal carcinomas.

The cytomegalovirus-encoded chemokine receptor US28 promotes intestinal neoplasia in transgenic mice

US28 is a constitutively active chemokine receptor encoded by CMV (also referred to as human herpesvirus 5), a highly prevalent human virus that infects a broad spectrum of cells, including intestinal epithelial cells (IECs). To study the role of US28 in vivo, we created transgenic mice (VS28 mice) in which US28 expression was targeted to IECs. Expression of US28 was detected in all IECs of the small and large intestine, including in cells expressing leucine rich repeat containing GPCR5 (Lgr5), a marker gene of intestinal epithelial stem cells. US28 expression in IECs inhibited glycogen synthase 3β (GSK-3β) function, promoted accumulation of β-catenin protein, and increased expression of Wnt target genes involved in the control of the cell proliferation. VS28 mice showed a hyperplastic intestinal epithelium and, strikingly, developed adenomas and adenocarcinomas by 40 weeks of age. When exposed to an inflammation-driven tumor model (azoxymethane/dextran sodium sulfate), VS28 mice developed a significantly higher tumor burden than control littermates. Transgenic coexpression of the US28 ligand CCL2 (an inflammatory chemokine) increased IEC proliferation as well as tumor burden, suggesting that the oncogenic activity of US28 can be modulated by inflammatory factors. Together, these results indicate that expression of US28 promotes development of intestinal dysplasia and cancer in transgenic mice and suggest that CMV infection may facilitate development of intestinal neoplasia in humans.

Sensitive detection of human cytomegalovirus in tumors and peripheral blood of patients diagnosed with glioblastoma

Human cytomegalovirus (HCMV) has been described to be associated with several human malignancies, though the frequency of detection remains controversial. It is unclear whether HCMV plays an active role in malignant tumor progression or becomes reactivated under pathologic conditions that result in chronic inflammation or immunosuppression. In this study, we report on the investigation of detecting HCMV in the tumors and peripheral blood of patients with newly diagnosed glioblastoma multiforme (GBM). Using immunohistochemistry, in situ hybridization, and polymerase chain reaction amplification of viral DNA, the detection of HCMV was investigated in tumor and blood specimens from patients with GBM as well as in the peripheral blood of normal volunteers and patients undergoing craniotomy for diagnoses other than GBM. We found that a high percentage (>90%) of GBM tumors, not surrounding normal brain, are associated with HCMV nucleic acids and proteins. Furthermore, a significant proportion of patients (80%) with newly diagnosed GBM have detectable HCMV DNA in their peripheral blood, while sero-positive normal donors and other surgical patients did not exhibit detectable virus, suggesting either a systemic reactivation of HCMV within patients with GBM or shedding of viral DNA from infected tumor cells into the periphery. These results confirm the association of HCMV with malignant gliomas and demonstrate that subclinical HCMV viremia (presence of viral DNA in blood without clinical symptoms of infection) is a previously unrecognized disease spectrum in patients with GBM.

De novo gastrointestinal tumours after renal transplantation: role of CMV and EBV viruses

The development of new and more effective immunosuppressive agents has provided long-term survival for transplant recipients, thereby increasing the risk of de novo malignancy in chronic immunocompromised hosts. While de novo post-transplant lymphoproliferative diseases and skin cancer has been shown to have an increased incidence in long-term surviving solid organ transplant recipients, the association with gastrointestinal (GI) cancer is controversial. Over 12 yr, 20 patients (5%) out of 395 renal transplant recipients developed 23 de novo tumours; 11 skin cancer and 12 non-skin cancer. Four patients (1%) developed de novo tumours of the GI tract (three colon, and one gastric cancer). Immediately after tumour's diagnosis, immunosuppressive therapy was reduced; all patients were shifted from cyclosporine to Rapamicine within 30 d. The tumour was surgically resected with curative intent in three cases, while one patient had only palliative surgery because of metastatic disease. The post-operative courses was uneventful. All patients maintained normal graft function. However, three out of four patients (75%) died of progression of the neoplasm, within a median time from the diagnosis of 12 months. Further, we investigated a possible correlations between de novo GI cancer and HCV, HBV status, infections, cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivation, episodes of rejection, and blood transfusions. All cases with GI de novo cancers reported in this paper developed CMV and EBV reactivation within three months after transplantation. Thereafter we suggest a closer follow-up for de novo GI cancer in renal transplants with early CMV and EBV reactivation in order to avoid delayed diagnosis.

Cytomegalovirus infection in ulcerative colitis

OBJECTIVE

Cytomegalovirus (CMV) infection has been reported as an exacerbating factor in inflammatory bowel disease but the relationship between CMV infection and ulcerative colitis (UC) remains unclear. There has been no detailed research to elucidate the clinicopathologic features of CMV infection in UC using surgical specimens. The aim of this study was to investigate the clinicopathologic features of CMV infection in UC patients who had undergone colectomy.

MATERIAL AND METHODS

Surgical specimens taken from UC patients were examined for CMV infection. The patients were divided into three groups: severe, refractory, and UC-associated dysplasia or cancer according to the operative indications. CMV infection rates were evaluated and a comparison of clinical parameters was made between CMV-positive and CMV-negative patients, and the risk factors for CMV infection were analyzed using multivariate analyses.

RESULTS

It was found that 25% of 32 patients were positive for CMV in the severe UC group; 8.3% of 72 patients were positive for CMV in the refractory UC group. None of the 22 patients was positive for CMV in the UC-associated dysplasia or cancer group. The CMV-positive rate in the severe UC group was significantly higher than that in the other groups (p<0.05). Patients' age at the time of operation was higher in the CMV-positive group than in the CMV-negative group among the patients with severe UC (p<0.01), and age at operation was an independent risk factor for CMV infection.

CONCLUSIONS

CMV is found more frequently in severe UC than refractory UC and UC-associated cancer or dysplasia. Higher age can be a risk factor for CMV infection in patients with severe UC. However, a high steroid dose may not always be a risk factor for CMV infection.

Lack of association of cytomegalovirus with human brain tumors

Cytomegalovirus (CMV) is thought to possess oncogenic properties and has been linked with a number of human malignancies. CMV infection was recently described in association with malignant gliomas. The intent of the present study was to further investigate the reported association between CMV and malignant gliomas. Tissue from 22 brain tumors of various histologic types and grades, four normal brains, six breast carcinomas, six colon carcinomas, six lung carcinomas, and six sarcomas were evaluated for the presence of CMV by polymerase chain reaction (PCR), in situ hybridization, and immunohistochemical methods. None of the brain tumors or normal brain tissue tested demonstrated evidence of CMV pp65 or early nuclear proteins by immunohistochemistry. In addition, no CMV RNA or DNA was detected in these cases by in situ hybridization and PCR. None of the carcinomas or sarcomas evaluated were positive for CMV by immunohistochemistry, in situ hybridization, or PCR. The findings of the present study suggest that CMV is not significantly associated with brain tumors in humans.

Cytomegalovirus is not associated with progression and metastasis of colorectal cancer

Recently, it was hypothesized that human cytomegalovirus (HCMV) might be associated with colorectal cancer progression. However, the role of HCMV infection in colorectal cancer remains controversial. We aimed to assess whether nucleic acids and/or gene products of HCMV could be detected in primary and metastatic colorectal carcinomas. Fresh-frozen biopsy specimens from 77 primary and metastatic colorectal carcinomas of randomly selected patients were analyzed by PCR and immunohistochemistry. We investigated 57 primary tumors and 20 metastases, comprising 13 tumor pairs from the same patient. In PCR, four primary tumors showed a positive CMV result whereas all investigated metastases were negative including three paired samples from positive primaries. In immunohistochemistry, no specific staining could be determined in all neoplastic epithelial cells. In summary, we think that there is no association between CMV infection and tumor progression or metastasis formation of colorectal cancer.

Specific localisation of human cytomegalovirus nucleic acids and proteins in human colorectal cancer

BACKGROUND

Colorectal cancer is the second most frequent cause of death from cancer in the USA, and most tumours arise sporadically with no clear cause or genetic predisposition. Human cytomegalovirus is a beta-herpesvirus that is endemic in the human population and can cause life-threatening disease in immunosuppressed adults. In vitro, human cytomegalovirus can transform cells and dysregulate many cellular pathways relevant to colon adenocarcinoma pathogenesis, especially those affecting the cell cycle, mutagenesis, apoptosis, angiogenesis, and cyclo-oxygenase-2 (COX-2) expression. We aimed to assess whether gene products of human cytomegalovirus could be detected in colorectal cancers.

METHODS

We obtained formalin-fixed, paraffin-embedded pathological specimens of colorectal polyps, adenocarcinomas, and adjacent normal mucosa from 29 patients. To detect human cytomegalovirus proteins and nucleic acids, we used immunohistochemistry with two different monoclonal antibodies, in-situ hybridisation, and PCR with DNA sequencing.

FINDINGS

Human cytomegalovirus proteins IE1-72 and pp65 were detected in a tumour cell-specific pattern in 14 (82%) of 17 and seven (78%) of nine colorectal polyps, respectively, and 12 (80%) of 15 and 11 (92%) of 12 adenocarcinomas, respectively, but not in adjacent non-neoplastic colon biopsy samples from the same patients (none of seven and none of two, respectively). Human cytomegalovirus infection of colon-cancer cells (Caco-2) in vitro resulted in specific induction of Bcl-2 and cyclo-oxygenase-2 proteins, both of which are thought to contribute to progression of colon cancer.

INTERPRETATION

Human cytomegalovirus nucleic acids and proteins can be found that specifically localise to neoplastic cells in human colorectal polyps and adenocarcinomas, and virus infection can induce important oncogenic pathways in colon-cancer cells.

Human cytomegalovirus and human herpesvirus 6 genes that transform and transactivate

This review is an update on the transforming genes of human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6). Both viruses have been implicated in the etiology of several human cancers. In particular, HCMV has been associated with cervical carcinoma and adenocarcinomas of the prostate and colon. In vitro transformation studies have established three HCMV morphologic transforming regions (mtr), i.e., mtrI, mtrII, and mtrIII. Of these, only mtrII (UL111A) is retained and expressed in both transformed and tumor-derived cells. The transforming and tumorigenic activities of the mtrII oncogene were localized to an open reading frame (ORF) encoding a 79-amino-acid (aa) protein. Furthermore, mtrII protein bound to the tumor suppressor protein p53 and inhibited its ability to transactivate a p53-responsive promoter. In additional studies, the HCMV immediate-early protein IE86 (IE2; UL122) was found to interact with cell cycle-regulatory proteins such as p53 and Rb. However, IE86 exhibited transforming activity in vitro only in cooperation with adenovirus E1A. HHV-6 is a T-cell-tropic virus associated with AIDS-related and other lymphoid malignancies. In vitro studies identified three transforming fragments, i.e., SalI-L, ZVB70, and ZVH14. Of these, only SalI-L (DR7) was retained in transformed and tumor-derived cells. The transforming and tumorigenic activities of SalI-L have been localized to a 357-aa ORF-1 protein. The ORF-1 protein was expressed in transformed cells and, like HCMV mtrII, bound to p53 and inhibited its ability to transactivate a p53-responsive promoter. HHV-6 has also been proposed to be a cofactor in AIDS because both HHV-6 and human immunodeficiency virus type 1 (HIV-1) have been demonstrated to coinfect human CD4(+) T cells, causing accelerated cytopathic effects. Interestingly, like the transforming proteins of DNA tumor viruses such as simian virus 40 and adenovirus, ORF-1 was also a transactivator and specifically up-regulated the HIV-1 long terminal repeat when cotransfected into CD4(+) T cells. Finally, based on the interactions of HCMV and HHV-6 transforming proteins with tumor suppressor proteins, a scheme is proposed for their role in oncogenesis.

Meconium aspiration syndrome

Background

A possible association between human cytomegalovirus (HCMV) infection and colorectal cancer progression has been inferred by the identification in tumour tissues of HCMV antigens and specific viral DNA or RNA sequences. To further investigate the relationship between HCMV and colorectal cancers we developed qualitative and quantitative PCR assay to detect HCMV DNA in 56 formalin-fixed paraffin-embedded (FFPE) tissue samples from patients belonging to 4 different histological phenotypes: adenoma; poorly, moderately and well differentiated adenocarcinomas.

Results

Of the 56 FFPE tested tissue samples, 6 (11%) were positive for HCMV nested PCR amplification, and more precisely 1 (5%) of 20 cases of adenoma and 5 (21%) of 24 cases of moderately differentiated adenocarcinoma. No PCR positivity was obtained in samples from well and poorly differentiated adenocarcinomas.

Conclusion

Our observations suggest that there is no evidence of a direct association between HCMV and colorectal cancer. Moreover, the results obtained are not supportive of a causal role of HCMV in the processes of carcinogenesis and/or progression of colorectal cancer. However, the fact that the virus may present a "hit and run" like-mechanism and HCMV can thus only be detectable at a particular stage of a processing adenocarcinoma, suggests that a significant number of colorectal cancers might have been the subject of HCMV infection that could contribute to trigger the oncogenic differentiation. Our analysis does not exclude the possibility of HCMV infection subsequent viral clearance.

Humoral reaction in the inflamed colon in Hirschsprung's disease and ulcerative colitis

An immunological study of B cells in patients with colitis that was associated with Hirschsprung's disease was undertaken and compared with that in patients with ulcerative colitis and in normal controls. There was an appreciable increase in IgA and a decrease in IgG in both disease groups. Humoral reaction in colitis associated with Hirschsprung's disease seems to be indistinguishable from that in ulcerative colitis and possibly in other inflammatory bowel diseases.

The status of CMV as a human pathogen

Cytomegalovirus (CMV) is a common infectious agent which is well adapted to its host. Following primary infection, which is almost always asymptomatic in people with normal immunity, the virus establishes latency at sites which are unknown. The virus is probably maintained in this latent state by immune surveillance mechanisms since immunosuppression frequently leads to reactivation of virus.

Cytomegalovirus has been identified in most anatomical areas of the human body. The aim of this article is to define criteria for pathogenicity so that clinical and experimental data can be reviewed to determine if CMV is likely to cause disease at these various clinical sites. Thus, patients have been shown to die frequentlywithCMV but do they diefromit?

Elution of cytomegalovirus antibodies from adenocarcinoma of the colon

Eluates were prepared by high salt extraction from normal colonic mucosa and adenocarcinomatous tissue from 28 patients, eight more from unmatched colonic tissue and five from patients with other gastrointestinal disease. Immunoglobulins were detected by ELISA: IgG was present in 24% eluates from normal colon and 21% from carcinomas; IgA in 55% eluates from normal colon and 39% from carcinomas; IgM in 55% from normal colon and 37% from carcinomas. Cytomegalovirus-specific antibody was found in 15% eluates from normal colon and in 18% carcinomas. Out of the 28 matched specimens, cytomegalovirus-specific IgG was detected in one normal and four tumour eluates, specific IgA in two normal and four tumour eluates, and specific IgM in two normal and two tumour eluates. In two instances cytomegalovirus-specific antibody was present in the eluates prepared from the normal and tumour tissue of the same patient. Of those eluates which contained cytomegalovirus-specific antibodies by ELISA, two were positive by anti-complement immunofluorescence of human embryo fibroblasts infected with cytomegalovirus strain AD-169. It seems possible, therefore, that cytomegalovirus antigens on colonic cells may be masked by complexing with anti-cytomegalovirus antibodies, and may not therefore be detected by techniques such as immunofluorescence.